Radio communication device and method for operating a radio communication device

ABSTRACT

According to an aspect of this disclosure, a radio communication device is provided comprising a first transceiver configured to transmit and receive signals in accordance with a Cellular Wide Area radio communication technology; a second transceiver configured to transmit and receive signals in accordance with a Short Range radio communication technology or a Metropolitan Area System radio communication technology; a first processor configured to control the first transceiver; and a second processor configured to control the second transceiver wherein the first processor is configured to control the first transceiver to transmit signals in accordance with a predefined transmitting schedule, wherein the first processor is further configured to control the first transceiver to omit transmitting signals within at least one of a time period and a frequency band provided for signal transmission of the first transceiver in accordance with the predefined transmitting schedule.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation and claims priority to U.S.application Ser. No. 13/833,534 filed on Mar. 15, 2013; which claimspriority to U.S. Provisional Application Ser. No. 61/618,908, filed Apr.2, 2012, all of which are incorporated by reference herein in theirentirety for all purposes.

TECHNICAL FIELD

The present disclosure relates to radio communication devices andmethods for operating a radio communication device.

BACKGROUND

Mobile communication terminals may support a plurality of radio accesstechnologies, e.g. a cellular radio communication technology, e.g. LTE(Long Term Evolution) and a Short Range radio communication technology(e.g. Bluetooth or WLAN) or a Metropolitan Area System radiocommunication technology such as WiMax. Although typically, differentfrequency bands are allocated to such different radio access technologythere may still be interference between them, for example when a mobilecommunication terminal wants to operate two different radio accesstechnologies in parallel. Avoiding such interference and improvingcoexistence between different radio access technologies is desirable.

SUMMARY

According to a non-limiting aspect of this disclosure, an apparatus isprovided including a first transceiver configured to transmit andreceive cellular wide area radio signals; a second transceiverconfigured to transmit and receive short range radio signals; at leastone processor configured to control the first transceiver to restricttransmit of cellular wide area radio signals within portions of time forcellular wide area radio signal transmission based on a hybrid automaticrepeat request process of the cellular wide area radio transmission whenexecuting a stored program.

According to another non-limiting aspect of this disclosure, a mobileradio device for reducing interference of a radio circuit is provided.The mobile radio device may include a first transceiver configured totransmit and receive cellular wide area radio signals, a secondtransceiver configured to transmit and receive short range radiosignals, and at least one processor. The processor(s) may be configuredto control the first transceiver to transmit signals based on apredefined transmitting schedule and restrict transmitting signalswithin a time period for cellular wide area radio signal transmissionbased on the predefined transmitting schedule where the predefinedtransmitting schedule comprises a transmitting and receiving frameincluding time slots for transmitting and receiving cellular wide arearadio signals. The processor may be further configured to select thetime period in which the first transceiver restricts transmittingsignals based on a hybrid automatic repeat request process of thecellular wide area radio communication and then control the firsttransceiver to restrict transmitting signals in the time period.

According to another non-limiting aspect of this disclosure, acommunication terminal is provided having at least a first transceiver,a second transceiver, at least one memory, and at least one processorwhere the the first and second transceivers have frontend components andantennas. The processor may be configured to control the firsttransceiver to restrict transmission of cellular wide area radio signalswithin portions of time for cellular wide area radio signal transmissionbased on a hybrid automatic repeat request process of the cellular widearea radio transmission.

According to another non-limiting aspect of this disclosure, a computerreadable medium may have stored code thereon that implements anoperation of an apparatus for reducing interference.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the invention. In the following description, variousaspects are described with reference to the following drawings, inwhich:

FIG. 1 shows a communication system according to an aspect of thisdisclosure.

FIG. 2 shows a frequency band diagram.

FIG. 3 shows a test system.

FIG. 4 shows the measurement results of the first test case.

FIG. 5 shows modified measurement results for the first test case for adifferent wide band noise.

FIG. 6 shows the measurement results of the second test case.

FIG. 7 shows modified measurement results for the second test case for adifferent wide band noise.

FIG. 8 shows the measurement results of the second test case.

FIG. 9 shows modified measurement results for the second test case for adifferent wide band noise.

FIG. 10 shows a communication terminal according to various aspects ofthis disclosure.

FIG. 11 shows a frame structure.

FIG. 12 shows a data transmission diagram.

FIG. 13 shows a transmission diagram.

FIG. 14 shows a transmission diagram.

FIG. 15 shows a transmission diagram.

FIGS. 16 and 17 depict the impact of WLAN and Bluetooth use cases overLTE-FDD for full connectivity traffic support, relying only on LTEdenial and LTE kill.

FIG. 18 shows a communication circuit according to an aspect of thisdisclosure.

FIG. 19 shows a status & arbitration unit according to an aspect of thisdisclosure.

FIG. 20 shows a transmission diagram.

FIG. 21 shows a communication terminal.

FIG. 22 shows a flow diagram.

FIG. 23 shows a transmission diagram.

FIG. 24 shows a message flow diagram.

FIG. 25 shows a frequency allocation diagram.

FIG. 26 shows a message flow diagram.

FIG. 27 shows a transmission diagram.

FIG. 28 shows a transmission diagram.

FIG. 29 shows a transmission diagram.

FIG. 30 shows transmission diagrams.

FIG. 31 shows a transmission diagram.

FIG. 32 shows a transmission diagram.

FIG. 33 shows a transmission diagram.

FIG. 34 shows a radio communication device.

FIG. 35 shows a flow diagram.

FIG. 36 shows a message flow diagram illustrating a process for BT/LTEcoexistence.

FIG. 37 shows a message flow diagram illustrating a process for BT/LTEcoexistence.

FIG. 38 shows a message flow diagram illustrating a process for WiFi/LTEcoexistence.

FIG. 39 shows a message flow diagram illustrating a process for WiFi/LTEcoexistence.

DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details and aspects of thisdisclosure in which the invention may be practiced. These aspects ofthis disclosure are described in sufficient detail to enable thoseskilled in the art to practice the invention. Other aspects of thisdisclosure may be utilized and structural, logical, and electricalchanges may be made without departing from the scope of the invention.The various aspects of this disclosure are not necessarily mutuallyexclusive, as some aspects of this disclosure can be combined with oneor more other aspects of this disclosure to form new aspects.

3GPP (3rd Generation Partnership Project) has introduced LTE (Long TermEvolution) into the Release 8 version of UMTS (Universal MobileTelecommunications System) standards.

The air interface of an LTE communication system is called E-UTRA(Evolved Universal Terrestrial Radio Access) and is commonly referred toas ‘3.9G’. In December 2010, the ITU recognized that current versions ofLTE and other evolved 3G technologies that do not fulfill “IMT-Advanced”requirements could nevertheless be considered ‘4G’, provided theyrepresent forerunners to IMT-Advanced and “a substantial level ofimprovement in performance and capabilities with respect to the initialthird generation systems deployed already. LTE is therefore sometimealso referred to as ‘4G’ (mainly for marketing reasons).

In comparison with its predecessor UMTS, LTE offers an air interfacethat has been further optimized for packet data transmission byimproving the system capacity and the spectral efficiency. Among otherenhancements, the maximum net transmission rate has been increasedsignificantly, namely to 300 Mbps in the downlink transmission directionand to 75 Mbps in the uplink transmission direction. LTE supportsscalable bandwidths of from 1.4 MHz to 20 MHz and is based on newmultiple access methods, such as OFDMA (Orthogonal Frequency DivisionMultiple Access)/TDMA (Time Division Multiple Access) in downlinkdirection (tower, i.e. base station, to handset, i.e. mobile terminal)and SC-FDMA (Single Carrier-Frequency Division Multiple Access)/TDMA inuplink direction (handset to tower). OFDMA/TDMA is a multicarriermultiple access method in which a subscriber (i.e. a mobile terminal) isprovided with a defined number of subcarriers in the frequency spectrumand a defined transmission time for the purpose of data transmission.The RF (Radio Frequency) capability of a mobile terminal according toLTE (also referred to as User Equipment (UE), e.g. a cell phone) fortransmission and reception has been set to 20 MHz. A physical resourceblock (PRB) is the baseline unit of allocation for the physical channelsdefined in LTE. It includes a matrix of 12 subcarriers by 6 or 7OFDMA/SC-FDMA symbols. At the physical layer a pair of one OFDMA/SC-FDMAsymbol and one subcarrier is denoted as a ‘resource element’. Acommunication system that is used according to an aspect of thisdisclosure and which for example a communication system according to LTEis described in the following with reference to FIG. 1.

FIG. 1 shows a communication system 100 according to an aspect of thisdisclosure.

The communication system 100 is a cellular mobile communication system(also referred to as cellular radio communication network in thefollowing) including a radio access network (e.g. an E-UTRAN, EvolvedUMTS (Universal Mobile Communications System) Terrestrial Radio AccessNetwork according to LTE (Long Term Evolution)) 101 and a core network(e.g. an EPC, Evolved Packet Core, according LTE) 102. The radio accessnetwork 101 may include base (transceiver) stations (e.g. eNodeBs, eNBs,according to LTE) 103. Each base station 103 provides radio coverage forone or more mobile radio cells 104 of the radio access network 101.

A mobile terminal (also referred to as UE, user equipment) 105 locatedin a mobile radio cell 104 may communicate with the core network 102 andwith other mobile terminals 105 via the base station providing coveragein (in other words operating) the mobile radio cell. In other words, thebase station 103 operating the mobile radio cell 104 in which the mobileterminal 105 is located provides the E-UTRA user plane terminationsincluding the PDCP (Packet Data Convergence Protocol) layer, the RLC(Radio Link Control) layer and the MAC (Medium Access Control) layer andcontrol plane terminations including the RRC (Radio Resource Control)layer towards the mobile terminal 105.

Control and user data are transmitted between a base station 103 and amobile terminal 105 located in the mobile radio cell 104 operated by thebase station 103 over the air interface 106 on the basis of a multipleaccess method.

The base stations 103 are interconnected with each other by means of afirst interface 107, e.g. an X2 interface. The base stations 103 arealso connected by means of a second interface 108, e.g. an S1 interface,to the core network, e.g. to an MME (Mobility Management Entity) 109 viaa S1-MME interface and to a Serving Gateway (S-GW) 110 by means of anS1-U interface. The S1 interface supports a many-to-many relationbetween MMEs/S-GWs 109, 110 and the base stations 103, i.e. a basestation 103 can be connected to more than one MME/S-GW 109, 110 and anMME/S-GW can 109, 110 be connected to more than one base station 103.This enables network sharing in LTE.

For example, the MME 109 may be responsible for controlling the mobilityof mobile terminals located in the coverage area of E-UTRAN, while theS-GW 110 is responsible for handling the transmission of user databetween mobile terminals 105 and core network 102.

In case of LTE, the radio access network 101, i.e. the E-UTRAN 101 incase of LTE, can be seen to consist of the base station 103, i.e. theeNBs 103 in case of LTE, providing the E-UTRA user plane (PDCP/RLC/MAC)and control plane (RRC) protocol terminations towards the UE 105.

An eNB 103 may for example host the following functions:

-   -   Functions for Radio Resource Management: Radio Bearer Control,        Radio Admission Control, Connection Mobility Control, dynamic        allocation of resources to UEs 105 in both uplink and downlink        (scheduling);    -   IP header compression and encryption of user data stream;    -   Selection of an MME 109 at UE 105 attachment when no routing to        an MME 109 can be determined from the information provided by        the UE 105;    -   Routing of User Plane data towards Serving Gateway (S-GW) 110;    -   Scheduling and transmission of paging messages (originated from        the MME);    -   Scheduling and transmission of broadcast information (originated        from the MME 109 or O&M (Operation and Maintenance));    -   Measurement and measurement reporting configuration for mobility        and scheduling;    -   Scheduling and transmission of PWS (Public Warning System, which        includes ETWS (Earthquake and Tsunami Warning System) and CMAS        (Commercial Mobile Alert System)) messages (originated from the        MME 109);    -   CSG (Closed Subscriber Group) handling.

Each base station of the communication system 100 controlscommunications within its geographic coverage area, namely its mobileradio cell 104 that is ideally represented by a hexagonal shape. Whenthe mobile terminal 105 is located within a mobile radio cell 104 and iscamping on the mobile radio cell 104 (in other words is registered withthe mobile radio cell 104) it communicates with the base station 103controlling that mobile radio cell 104. When a call is initiated by theuser of the mobile terminal 105 (mobile originated call) or a call isaddressed to the mobile terminal 105 (mobile terminated call), radiochannels are set up between the mobile terminal 105 and the base station103 controlling the mobile radio cell 104 in which the mobile station islocated (and on which it is camping). If the mobile terminal 105 movesaway from the original mobile radio cell 104 in which a call was set upand the signal strength of the radio channels established in theoriginal mobile radio cell 104 weakens, the communication system mayinitiate a transfer of the call to radio channels of another mobileradio cell 104 into which the mobile terminal 105 moves.

As the mobile terminal 105 continues to move throughout the coveragearea of the communication system 100, control of the call may betransferred between neighboring mobile radio cells 104. The transfer ofcalls from mobile radio cell 104 to mobile radio cell 104 is termedhandover (or handoff).

In addition to the communication via the E-UTRAN 102, the mobileterminal 105 may support communication via a Bluetooth (BT)communication connection 111, for example to another mobile terminal 112and communication a WLAN communication connection 113 to a WLAN accesspoint (AP) 114. Via the access point 114, the mobile terminal may accessa communication network 115 (e.g. the Internet) which may be connectedto the core network 102.

LTE operates in a newly allocated set of frequency bands. The majordifference introduced by this new set of bands compared to those usedfor 2G/3G communication systems is that two of them are in the immediatevicinity of the ISM band where WLAN and Bluetooth operate.

This is illustrated in FIG. 2.

FIG. 2 shows a frequency band diagram 200.

In the band diagram 200, frequency includes from left to right.

From left to right, LTE-Band 40 201, ISM band 202, LTE-Band 7 UL(Uplink), a guard band 204, LTE-Band 38 205 and LTE-Band 7 DL (Downlink)206 are shown. The band diagram 200 thus illustrates the spectrumallocated to LTE around the ISM band 202.

LTE-Band 40 201 used by LTE-TDD (Time Division Duplex) is immediatelycontiguous to the lower band of the ISM band 202 without any guard bandin between and LTE-Band 7 204 used for LTE-FDD (Frequency DivisionDuplex) UL is contiguous to the higher band of the ISM band 202 with theguard band 203 of 17 MHz.

In the following, in order to illustrate the coexistence problems are(in this example between LTE) results of real measurements carried outwith current hardware are given. The three test cases for which resultsare given are:

1: WLAN affecting band 40;2: LTE band 40 disturbing WLAN in the ISM band;3: LTE Band 7 disturbing WLAN in the ISM band.

The test system used is illustrated in FIG. 3.

FIG. 3 shows a test system 300.

The test system 300 includes a first communication circuit 301supporting (among others) WLAN and Bluetooth and a second communicationcircuit 302 supporting (among others) LTE communication. Various filter303, 304, 305, 306 are provided for the testing.

An arrow 307 indicates the coexistence case of interest in this example(WLAN/LTE coexistence). It should be noted that in the measurements, theRF (radio frequency) analysis has focused on interference via theantennas, and not via pin to pin interference on IC level.

In the first test case, LTE-Band 40 201 is the receiver (or interferencevictim) and ISM band 202 is the interferer.

FIG. 4 shows the measurement results of the first test case.

FIG. 5 shows modified measurement results for the first test case for adifferent wide band noise.

From the first test case, it can be seen that using the lower part ofthe ISM band desensitizes the whole band 40.

In the second test case, LTE-Band 40 201 is the interferer and ISM band202 is the receiver (or interference victim).

FIG. 6 shows the measurement results of the second test case.

FIG. 7 shows modified measurement results for the second test case for adifferent wide band noise.

From the second test case, it can be seen that using the higher part ofband 40 desensitizes the whole ISM band. Roughly 75% of the frequencycombinations have more than 10 dB of desensitization.

In the third test case, LTE-Band 7 UL 204 is the interferer and ISM band202 is the receiver (or interference victim).

FIG. 8 shows the measurement results of the second test case.

FIG. 9 shows modified measurement results for the second test case for adifferent wide band noise.

From the third test case, it can be seen that even with a narrow WLANfilter there is a severe desensitization at the frequency 2510 MHz.

It can be seen from the test results that with existing hardware severecoexistence problems arise in all three test cases.

According to various aspects of this disclosure, these issues are solvedor mitigated using mechanisms applied at PHY level and protocol leveland for example relying on a mixture of software (SW) and hardware (HW)implementations.

Examples are described in the following with reference to an exemplarycommunication terminal as illustrated in FIG. 10.

FIG. 10 shows a communication terminal 1000 according to various aspectsof this disclosure.

For example, the communication terminal 1000 is a mobile radiocommunication device configured in accordance with LTE and/or other 3GPPmobile radio communication technologies. The communication terminal 1000is also also referred to as radio communication device.

In various aspects of the disclosure, the communication terminal 1000may include a processor 1002, such as e.g. a microprocessor (e.g. acentral processing unit (CPU)) or any other type of programmable logicdevice (which may for example act as controller). Furthermore, thecommunication terminal 1000 may include a first memory 1004, e.g. a readonly memory (ROM) 1004 and/or a second memory 1006, e.g. a random accessmemory (RAM) 1006. Moreover, the communication terminal 1000 may includea display 1008 such as e.g. a touch sensitive display, e.g. a liquidcrystal display (LCD) display or a light emitting diode (LED) display,or an organic light emitting diode (OLED) display. However, any othertype of display may be provided as the display 1008. The communicationterminal 1000 may in addition include any other suitable output device(not shown) such as e.g. a loudspeaker or a vibration actuator. Thecommunication terminal 1000 may include one or more input devices suchas keypad 1010 including a plurality of keys. The communication terminal1000 may in addition include any other suitable input device (not shown)such as e.g. a microphone, e.g. for speech control of the communicationterminal 1000. In case the display 1008 is implemented as a touchsensitive display 1008, the keypad 1010 may be implemented by the touchsensitive display 1008. Moreover, optionally, the communication terminal1000 may include a co-processor 1012 to take processing load from theprocessor 1002. Furthermore, the communication terminal 1000 may includea first transceiver 1014 and a second transceiver 1018. The firsttransceiver 1014 is for example an LTE transceiver supporting radiocommunication according to LTE and the second transceiver 1018 is forexample a WLAN transceiver supporting communication according to a WLANcommunication standard or a Bluetooth transceiver supportingcommunication according to Bluetooth.

The above described components may be coupled with each other via one ormore lines, e.g. implemented as a bus 1016. The first memory 1004 and/orthe second memory 1006 may be a volatile memory, for example a DRAM(Dynamic Random Access Memory) or a non-volatile memory, for example aPROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM(Electrically Erasable PROM), or a flash memory, e.g., a floating gatememory, a charge trapping memory, an MRAM (Magnetoresistive RandomAccess Memory) or a PCRAM (Phase Change Random Access Memory) or a CBRAM(Conductive Bridging Random Access Memory). The program code used to beexecuted and thereby to control the processor 1002 (and optionally theco-processor 1012) may be stored in the first memory 1004. Data (e.g.the messages received or to be transmitted via the first transceiver1014) to be processed by the processor 1002 (and optionally theco-processor 1012) may be stored in the second memory 1006. The firsttransceiver 1014 may be configured such that it implements a Uuinterface in accordance with LTE. The communication terminal 1000 andthe first transceiver 1014 may also be configured to provide MIMO radiotransmission.

Moreover, the communication terminal 1000 may include a still imageand/or video camera 1020, configured to provide a video conference viathe communication terminal 1000.

Furthermore, the communication terminal 1000 may include a SubscriberIdentity Module (SIM), e.g. a UMTS Subscriber Identity Module (USIM)identifying a user and subscriber of the communication terminal 1000.The processor 1002 may include audio processing circuits such as e.g.audio decoding circuit and/or audio encoding circuit, configured todecode and/or encode audio signals in accordance with one or more of thefollowing audio encoding/decoding technologies: ITU G.711, AdaptiveMulti-Rate Narrowband (AMR-NB), Adaptive Multi-Rate Wideband (AMR-WB),Advanced Multi-Band Excitation (AMBE), etc.

It should be noted that while most of the examples described below aredescribed for the coexistence of LTE and WLAN or Bluetooth, the firsttransceiver 1014 and the second transceiver 1018 may also support othercommunication technologies.

For example, each of the transceivers 1014, 1018 may support one of thefollowing communication technologies:

-   -   a Short Range radio communication technology (which may include        e.g. a Bluetooth radio communication technology, an Ultra Wide        Band (UWB) radio communication technology, and/or a Wireless        Local Area Network radio communication technology (e.g.        according to an IEEE 802.11 (e.g. IEEE 802.11n) radio        communication standard)), IrDA (Infrared Data Association),        Z-Wave and ZigBee, HiperLAN/2 ((High PErformance Radio LAN; an        alternative ATM-like 5 GHz standardized technology), IEEE        802.11a (5 GHz), IEEE 802.11g (2.4 GHz), IEEE 802.11n, IEEE        802.11VHT (VHT=Very High Throughput),    -   a Metropolitan Area System radio communication technology (which        may include e.g. a Worldwide Interoperability for Microwave        Access (WiMax) (e.g. according to an IEEE 802.16 radio        communication standard, e.g. WiMax fixed or WiMax mobile),        WiPro, HiperMAN (High Performance Radio Metropolitan Area        Network) and/or IEEE 802.16m Advanced Air Interface,    -   a Cellular Wide Area radio communication technology (which may        include e.g. a Global System for Mobile Communications (GSM)        radio communication technology, a General Packet Radio Service        (GPRS) radio communication technology, an Enhanced Data Rates        for GSM Evolution (EDGE) radio communication technology, and/or        a Third Generation Partnership Project (3GPP) radio        communication technology (e.g. UMTS (Universal Mobile        Telecommunications System), FOMA (Freedom of Multimedia Access),        3GPP LTE (Long Term Evolution), 3GPP LTE Advanced (Long Term        Evolution Advanced)), CDMA2000 (Code division multiple access        2000), CDPD (Cellular Digital Packet Data), Mobitex, 3G (Third        Generation), CSD (Circuit Switched Data), HSCSD (High-Speed        Circuit-Switched Data), UMTS (3G) (Universal Mobile        Telecommunications System (Third Generation)), W-CDMA (UMTS)        (Wideband Code Division Multiple Access (Universal Mobile        Telecommunications System)), HSPA (High Speed Packet Access),        HSDPA (High-Speed Downlink Packet Access), HSUPA (High-Speed        Uplink Packet Access), HSPA+(High Speed Packet Access Plus),        UMTS-TDD (Universal Mobile Telecommunications        System-Time-Division Duplex), TD-CDMA (Time Division-Code        Division Multiple Access), TD-CDMA (Time Division-Synchronous        Code Division Multiple Access), 3GPP Rel. 8 (Pre-4G) (3rd        Generation Partnership Project Release 8 (Pre-4th Generation)),        UTRA (UMTS Terrestrial Radio Access), E-UTRA (Evolved UMTS        Terrestrial Radio Access), LTE Advanced (4G) (Long Term        Evolution Advanced (4th Generation)), cdmaOne (2G), CDMA2000        (3G) (Code division multiple access 2000 (Third generation)),        EV-DO (Evolution-Data Optimized or Evolution-Data Only), AMPS        (1G) (Advanced Mobile Phone System (1st Generation)), TACS/ETACS        (Total Access Communication System/Extended Total Access        Communication System), D-AMPS (2G) (Digital AMPS (2nd        Generation)), PTT (Push-to-talk), MTS (Mobile Telephone System),        IMTS (Improved Mobile Telephone System), AMTS (Advanced Mobile        Telephone System), OLT (Norwegian for Offentlig Landmobil        Telefoni, Public Land Mobile Telephony), MTD (Swedish        abbreviation for Mobiltelefonisystem D, or Mobile telephony        system D), Autotel/PALM (Public Automated Land Mobile), ARP        (Finnish for Autoradiopuhelin, “car radio phone”), NMT (Nordic        Mobile Telephony), Hicap (High capacity version of NTT (Nippon        Telegraph and Telephone)), CDPD (Cellular Digital Packet Data),        Mobitex, DataTAC, iDEN (Integrated Digital Enhanced Network),        PDC (Personal Digital Cellular), CSD (Circuit Switched Data),        PHS (Personal Handy-phone System), WiDEN (Wideband Integrated        Digital Enhanced Network), iBurst, Unlicensed Mobile Access        (UMA, also referred to as also referred to as 3GPP Generic        Access Network, or GAN standard)).

Short Range radio communication technologies may include the followingShort Range radio communication technology sub-families:

-   -   personal area networks (Wireless PANs) radio communication        sub-family, which may include e.g. IrDA (Infrared Data        Association), Bluetooth, UWB, Z-Wave and ZigBee; and    -   wireless local area networks (W-LANs) radio communication        sub-family, which may include e.g. HiperLAN/2 (High PErformance        Radio LAN; an alternative ATM-like 5 GHz standardized        technology), IEEE 802.11a (5 GHz), IEEE 802.11g (2.4 GHz), IEEE        802.11n, IEEE 802.11VHT (VHT=Very High Throughput).

Metropolitan Area System radio communication technology families mayinclude the following Metropolitan Area System radio communicationtechnology sub-families:

-   -   a Wireless campus area networks (W-CANs) radio communication        sub-family, which may be considered one form of a metropolitan        area network, specific to an academic setting, and which may        include e.g.WiMAX, WiPro, HiperMAN (High Performance Radio        Metropolitan Area Network), or IEEE 802.16m Advanced Air        Interface; and    -   a Wireless metropolitan area networks (W-MANs) radio        communication sub-family, which may be limited to a room,        building, campus or specific metropolitan area (e.g., a city)        respectively, and which may include e.g. WiMAX, WiPro, HiperMAN        (High Performance Radio Metropolitan Area Network), or IEEE        802.16m Advanced Air Interface.

Cellular Wide Area radio communication technologies may also beconsidered as Wireless Wide Area Network (Wireless WAN) radiocommunication technologies.

In the following examples, it is assumed that the first transceiver 1014supports LTE communication and accordingly operates in the LTE frequencybands 201, 204, 205, 206. Accordingly, the first transceiver 1014 isalso referred to as LTE RF.

It is further assumed for the following examples that the secondtransceiver 1018 operates in ISM band 202 and supports WLANcommunication or Bluetooth communication.

The first transceiver 1014 includes a first communication circuit 1022which may perform various tasks related to the communication carried outby the first transceiver 1014 such as controlling transmission/receptiontimings etc. The first communication circuit 1022 may be seen as a(first) processor of the communication terminal 1000 and is for exampleconfigured to control the first transceiver 1014.

The second transceiver 1018 similarly includes a second communicationcircuit 1024 which may perform various tasks related to thecommunication carried out by the second transceiver 1018 such ascontrolling transmission/reception timings etc. The second transceiver1018 is also referred to as connectivity (system) or CWS. The secondcommunication circuit 1024 is also referred to as CWS chip orconnectivity chip. The second communication circuit 1024 may be seen asa (second) processor of the communication terminal 1000 and is forexample configured to control the second transceiver 1018.

Each of the first transceiver 1014 and the second transceiver 1018 mayfurther include frontend components (filters, amplifiers etc.) and oneor more antennas.

The first communication circuit 1022 may include a first real-time (RT)interface 1026 and a first non-real-time interface (NRT) 1028.Similarly, the second communication circuit 1024 may include a second RTinterface 1030 and a second NRT interface 1032. These interfaces 1026 to1032 are described in more detail in the following and may be used toexchange control information with the respective other components of thecommunication terminal 1000. The RT interfaces 1026, 1030 may forexample form an RT interface between the first communication circuit1022 and the second communication circuit 1024. Similarly, the NRTinterfaces 1028, 1032 may form an NRT interface between the firstcommunication circuit 1022 and the second communication circuit 1024.

It should be noted that a “circuit” may be understood as any kind of alogic implementing entity, which may be special purpose circuitry or aprocessor executing software stored in a memory, firmware, or anycombination thereof. Thus, a “circuit” may be a hard-wired logic circuitor a programmable logic circuit such as a programmable processor, e.g. amicroprocessor (e.g. a Complex Instruction Set Computer (CISC) processoror a Reduced Instruction Set Computer (RISC) processor). A circuit mayalso be a processor executing software, e.g. any kind of computerprogram, e.g. a computer program using a virtual machine code such ase.g. Java. Any other kind of implementation of the respective functionswhich will be described in more detail below may also be understood as acircuit in accordance with aspects of this disclosure.

RT Coexistence Mechanisms

According to one aspect of this disclosure, a real time coexistencearchitecture is provided which relies on two methods (or at least one ofthese methods), namely protocol synchronization and traffic arbitration.

Protocol synchronization may for example consist of two mechanisms:exploiting the available periods where the LTE RF 1014 is idle andorganizing the RF activity of the connectivity system 1018 so that RX(i.e. receiving) periods occur simultaneously to LTE RX periods and TX(i.e. transmission) periods occur simultaneously to LTE TX periods.Protocol synchronization may be achieved via the usage of LTE frameindication and LTE gaps indication signals which allow the secondtransceiver 1018 (WLAN or BT) to schedule its activity at appropriatetimes: i.e. when the LTE RF 1014 is idle or when the respectiveactivities are compatible (i.e. such that both the first transceiver1014 and the second transceiver 1018 are receiving or such that both thefirst transceiver 1014 and the second transceiver 1018 aretransmitting).

Traffic arbitration may consist of receiving the indication of theupfront CWS 1018 activity and of the upfront LTE RF 1014 activity andselecting the traffic which is allowed to proceed when a conflict isidentified. Traffic arbitration may be achieved via CWS activityindication used by a RT (real time) arbiter to derive CWS-kill andLTE-kill signals (to “kill” a frame or subframe for a communicationtechnology, i.e. to prohibit transmission via the communicationtechnology in the subframe or frame).

In the following, LTE frame indication in the LTE-TDD case (i.e. in casethat the LTE RF 1014 is operating in TDD mode) is described which isused for protocol synchronization according to one aspect of thisdisclosure.

Being a Time Division Duplex system, LTE-TDD has a unique framestructure containing both DL and UL subframes. This is illustrated inFIG. 11.

FIG. 11 shows a frame structure 1100.

The frame structure 1100 illustrates an LTE-TDD frame 1101 including DLsubframes, i.e. subframes allocated for downlink transmissions (in whichthe LTE RF 1024 receives data), UL subframes, i.e. subframes allocatedfor uplink transmissions (in which the LTE RF 1028 transmits data) andspecial (S) subframes which may for example be used as a guard time andpilot transmission.

There is a set of seven possible configurations defined in 3GPP for TDD.Whichever the selected configuration, the TDD frame structure contains aperiodic DL/UL pattern which can be communicated to the CWS chip 1024and which can be exploited by the connectivity system 1018 to schedulecommunication traffic.

The LTE-TDD frame structure is typically static or varies very rarely.It may be indicated to the CWS chip 1028 via NRT messaging via the NRTinterface 1032. The required synchronization between the CWS chip 1028and LTE-TDD frame timing may be performed via the RT interfaces 1026,1030 using a LTE-frame_sync signal 1102 as illustrated in FIG. 11.

The LTE frame start (i.e. the beginning of the each frame 1001) isindicated 1 ms in advance to the CWS chip 1024 via the pulse sent overthe RT interface between the first communication circuit 1022 and thesecond communication circuit 1024 (i.e. via the RT interfaces 1026,1030) 1 ms in advance.

Using the LTE frame sync signal coupled with the LTE frame structuresignaled via an NRT message, the CWS chip 1024 has full knowledge of theLTE-TDD frame and it can schedule its communication activityaccordingly.

This LTE-TDD frame structure signaling message over the NRT(coexistence) interface between the first communication circuit 1022 andthe second communication circuit 1024 (formed by NRT interfaces 1028,1032) has for example the format as illustrated in table 1.

TABLE 1 ID Message payload Info bits I/O Description 11 LTE-BITMAP 10 ×2 O 0 = special subframe 1 = RX LTE subframe 2 = TX LTE subframe

This message may be reduced to 3 bits (7 configurations only) andencoding of S sub frame structure may be added:

-   -   the seven UL/DL TDD frame configuration as defined in 3GPP: 3        bits    -   the nine special sub frame configurations: 4 bits

Considering that this message is a NRT message and that using animplicit LTE configuration encoding would require some LTE knowledge onthe connectivity chip 1024 it may be desirable to stick to the explicit20 bits encoding.

For LTE frame indication in the LTE-FDD (Frequency Division Duplex)case, LTE-band 7 UL 204 is the most relevant band. This is an uplinkband hence all subframes are UL subframes. Nevertheless, an LTE frameindication may also be used in this case in order to allow the CWS chip1024 to properly schedule its activity on the LTE UL sub frameboundaries. It can also be used by the CWS chip 1024 to synchronize itssystem clock over the LTE system clock.

When (traffic) arbitration gives medium access to the CWS 1018, this mayby definition hold till the end of the killed LTE sub frame, knowing thesubframe boundaries the CWS 1018 is able to apply scheduling in order tomaximize the amount of traffic transferred till the end of the killed(LTE) subframe.

In the following, LTE gap indication in case of LTE-FDD discontinuousreception (DRX) and discontinuous transmission (DTX) is described whichis used for protocol synchronization according to one aspect of thisdisclosure.

LTE has been designed to address the need for mobile Internet access.Internet traffic can be characterized by a high burstiness with highpeak data rates and long silence periods. In order to allow for batterysavings, an LTE system allows for DRX (discontinuous reception). Two DRXprofiles are supported which are addressed by short DRX and long DRX,respectively. For the reverse link, i.e. the uplink, in order toincrease system capacity, an LTE system allows for discontinuoustransmission (DTX).

For example, for VoLTE (Voice over LTE) isochronous traffic can beassumed. As the speech coder produces one packet every 20 ms, theunderlying periodicity of the LTE traffic can be exploited for WLAN andBT transmission during LTE silence periods.

As an example, for an inactivity period of two (the smallest allowedvalue in 3 GPP Release 9 for DRX Inactivity Time is 1), the UL/DLschedule is shown in FIG. 12.

FIG. 12 shows a data transmission diagram 1200.

In the data transmission diagram 1200, time increases from left toright. The data transmission diagram 1200 illustrates uplink LTE datatransmission 1201, downlink LTE data transmission 1202 and, on a bottomtimeline 1203, illustrates the times (in terms of subframes) which areavailable for the CWS 1024 due to DRX periods 1207.

A first hatching 1204 indicates periods available for the CWS 1024 (e.g.BT or WLAN), a second hatching 1205 indicates periods which may beavailable for the CWS 1024 and a third hatching 1206 indicates periodswhich are exploitable by the CWS 1024.

In the bottom timeline 1203 the periods are marked (by the firsthatching 1204 and the second hatching 1205) for which no LTE-UL activityis expected and thus could be given to the CWS 1024. It shall be notedthat interference free time needs to be given to the LTE transceiver1022 (specifically in its role as receiver) prior to the upcomingreception to settle the AGC (Automatic Gain Control) and potentiallyreacquire the signal. For short LTE DRX periods, this period isapproximately 300 μs, for long DRX periods it is less than 1.3 ms.

The LTE standard also offers a mechanism called Semi-PersistentScheduling (SPS) to reduce the signaling overhead in case of isochronoustransfer. In this case, the UL grant is implicitly given by the SPSschedule and the DRX period can start right after the reception of thescheduled TTI (Transmission Time Interval).

In the following, an RT algorithm for LTE-FDD gap indication which maybe used for protocol synchronization according to an aspect of thisdisclosure is described.

An LTE transmission gap may be created at any time by the communicationterminal 1000 following network deployed decision rules. The starts andends of these transmission are according to one aspect of thisdisclosure indicated to the CWS 1024 so that the CWS 1024 can scheduleits data traffic within the transmission gaps (e.g. in case that the CWS1024 performs WLAN communication or a Bluetooth communication using aprofile which is ACL (Asynchronous Connectionless Link) based).

In 3GPP release 9 there are three possible root causes to havetransmission gaps created: Measurement gaps, DRX/DTX and Autonomousmeasurement gaps.

A measurement (transmission) gap is known 34 ms or 74 ms in advance atLTE L1 level and is 6 ms long. A DRX/DTX (transmission) gap in asubframe is known after decoding the PDCCH (Packet Data Control Channel)in the previous subframe, i.e. much less than 1 ms in advance (forexample approximately 200 μs). However, a transmission gap decision canbe overruled in ad-hoc mode till 1.5 ms before the transmission gapstarts.

LTE gap signaling according to one aspect of this disclosure isillustrated in FIG. 13.

FIG. 13 shows a transmission diagram 1300.

The transmission diagram 1300 illustrates uplink LTE data transmission1301, downlink LTE data transmission 1302, uplink transmission gapsignaling 1303 and downlink transmission gap signaling 1304. Timeincreases from left to right.

In this example, there is an uplink transmission gap 1305 and a downlinktransmission gap 1306. The uplink transmission gap 1305 is signaled byan uplink transmission gap signal 1307 (UL gap envelop signal) and thedownlink transmission gap 1306 is signaled by a downlink transmissiongap signal 1308 (DL gap envelop signal), wherein the start and thetermination (end) of the transmission gaps 1305, 1306 are for exampleindicated 1 ms in advance to the CWS chip 1204 by the uplinktransmission gap signal 1307 and the downlink transmission gap signal1308, for example via the RT interface between the first communicationcircuit 1022 and the second communication circuit 1024.

It should be noted that under 3GPP Rel11—Work item “In DeviceCoexistence” newly defined transmission gaps triggered especially forcoexistence purpose may be introduced. The transmission gap signalingaccording to one aspect of this disclosure is compliant with these newtransmission gaps.

Practically, the timing advance of the DL gap envelop signal 1308 iskept short as the decision to go for a transmission gap can be takenduring the last DL sub-frame before the DL transmission gap and can bedone only once the PDCCH is decoded. For UL transmission gaps, decisionis also based on DL subframe decoding but there is a delay of roughly 4ms between DL and UL subframes. In addition, the UL transmission gapdecision can be overruled before it is applied until 1.5 ms before thetransmission gap start-up. Overruling requests posterior to this time,if any, are not applied. Therefore, UL transmission gap start-up can besignaled 1 ms in advance (<1.5 ms). Similarly, transmission gaptermination can be signaled 1 ms in advance maximum since a higher valuecould not be applied for 1 ms UL transmission gaps (1 subframe).According to one aspect of this disclosure, 1 ms advance signaling isretained for LTE transmission gap termination signaling as themaximization of the advance facilitates traffic scheduling on the sideof the CWS 1018.

As indicated in FIG. 13, the advance values are for example tadv₃: 150μs, tadv₄: 1 ms, tadv₁ and tadv₂: 1 ms.

It should be noted that optimum signaling for a transmission gap may beachieved by indicating the transmission gap start and the transmissiongap duration.

It should further be noted that protocol synchronization may also beused for LTE-TDD Discontinuous reception (DRX) and discontinuoustransmission (DTX).

In the following, arbitration of the LTE-TDD case is described.

Due to LTE resource usage and due to the WLAN/BT protocol requirements,perfectly synchronizing the protocols on each side and applying onlyconcurrent RX and concurrent TX may not be sufficient to support the usecases and some conflicting RX/TX events may occur.

FIGS. 14 and 15 illustrate conflicts between LTE-TDD operation andWLAN/BT operation that may occur.

FIG. 14 shows a transmission diagram 1400.

The transmission diagram 1400 illustrates the occurrence oftransmission-reception conflicts in case of synchronized LTE-TDD andWLAN traffic.

For each of three timelines 1401, 1402, 1403 WLAN downlink transmissionsare illustrated above and WLAN uplink transmissions are illustratedbelow the timelines 1401, 1402, 1403 wherein time increases from left toright and, for example, from top to bottom along the timelines 1401,1402, 1403. Further, LTE transmissions (or LTE subframe allocation)1404, 1405, 1406 are illustrated for the timelines 1401, 1402, 1403.

A hatching 1407 indicates RX/TX conflicts that may occur between theWLAN transmissions and LTE transmissions.

FIG. 15 shows a transmission diagram 1500.

The transmission diagram 1500 illustrates the occurrence of UL-DLconflicts in case of synchronized LTE-TDD and Bluetooth traffic.

For each of three timelines 1501, 1502, 1503 Bluetooth data transmissionis illustrated above and Bluetooth data reception is illustrated belowthe timelines 1501, 1502, 1503 wherein time increases from left to rightfor each of the timelines 1501, 1502, 1503. Further, LTE transmissions(or LTE subframe allocation) 1504, 1505, 1506 are illustrated for thetimelines 1501, 1502, 1503.

A hatching 1507 indicates UL/DL conflicts that may occur between theBluetooth transmissions and LTE transmissions.

RX/TX conflict may be handled via arbitration which potentially leads toLTE sub frame loss. Arbitration may be performed between WLAN/BT and LTEto determine whether the WLAN/BT traffic is allowed or not.

For example, when a WLAN/BT transmit event (by the second transceiver1018) is conflicting with a LTE-DL subframe (i.e. a scheduled receptionby the first transceiver 1014), real time arbitration is performed. Thearbitration process decides either to kill the WLAN/BT transmission toprotect the LTE-DL sub-frame or to let it occur. In the latter case,depending on RF interference level, the LTE-DL sub frame is likely notto be decoded by LTE PHY, i.e. the LTE physical layer (implemented bycomponents of the first transceiver 1014).

In the LTE-UL case, an arbitration decision may consist in allowingWLAN/BT reception or allowing an LTE-UL subframe (i.e. an LTEtransmission). FIGS. 14 and 15 can be seen to illustrate the impact ofWLAN and Bluetooth use cases over LTE-TDD for full connectivity trafficsupport (i.e. support of the communication by the second transceiver1018), relying only on LTE denial and LTE desense. This sets the worstcase for LTE-TDD side and can be used as reference to quantify theenhancement provided by coexistence mechanisms for LTE-TDD.

The RT arbitration may be an entity implemented by a mixture of HW andSW located in the LTE subsystem (e.g. in the first transceiver 1014)which handles synchronization of the first transceiver 1014 and thesecond transceiver 1018 via the real time (coexistence) interfacebetween the first transceiver 1014 and the second transceiver 1018(formed by the RT interfaces 1026, 1030), e.g. in the context given byan NRT arbiter decision. It derives RT arbitration and applies it ontothe first transceiver 1014 and the second transceiver 1018 (via the RTcoexistence interface).

For LTE-FDD, the interfering band is an UL band. LTE UL cannot be harmedby the CWS hence the arbitration's role is reduced to protect or not toprotect the WLAN/BT RX from LTE TX. When a conflict occurs, i.e. as aconsequence of mis-scheduling or insufficient medium access forconnectivity traffic, the arbitration may be applied. It leads either tokilling the LTE UL-sub-frame or to let it happen normally.

FIGS. 16 and 17 depict the impact of WLAN and Bluetooth use cases overLTE-FDD for full connectivity traffic support, relying only on LTEdenial and LTE kill. This sets the worst case for LTE-FDD side and canbe used as reference to quantify the enhancement provided by coexistencemechanisms for LTE-FDD.

FIG. 16 shows a transmission diagram 1600.

The transmission diagram 1600 illustrates the occurrence oftransmission-reception conflicts in case of synchronized LTE-FDD andWLAN traffic.

For each of four timelines 1601, 1602, 1603, 1604 WLAN downlinktransmissions are illustrated above and WLAN uplink transmissions areillustrated below the timelines 1601, 1602, 1603, 1604 wherein timeincreases from left to right. Further, LTE transmissions (or LTEsubframe allocation) 1605, 1606, 1607, 1608 are illustrated for thetimelines 1601, 1602, 1603, 1604.

A hatching 1609 indicates RX/TX conflicts that may occur between theWLAN transmissions and LTE transmissions.

FIG. 17 shows a transmission diagram 1700.

The transmission diagram 1700 illustrates the occurrence of UL-DLconflicts in case of synchronized LTE-FDD and Bluetooth traffic.

For each of three timelines 1701, 1702, 1703 Bluetooth data transmissionis illustrated above and Bluetooth data reception is illustrated belowthe timelines 1701, 1702, 1703 wherein time increases from left to rightfor each of the timelines 1701, 1702, 1703. Further, LTE transmissions(or LTE subframe allocation) 1704, 1705, 1706 are illustrated for thetimelines 1701, 1702, 1703.

A hatching 1707 indicates UL/DL conflicts that may occur between theBluetooth transmissions and LTE transmissions.

The real time (coexistence) interface 1026 may be implemented byhardware only or by a mixture of hardware and software located in theLTE subsystem (i.e. in the first transceiver 1014). According to oneaspect of this disclosure, it includes a set of eight proprietary realtime signals to support protocol synchronization and trafficarbitration. These signals may for example be controlled via a softwaredriver located in the LTE subsystem. It is connected to the CWS chip RTinterface 1030.

The RT interface may for example include the traffic arbitration signalsas shown in table 2.

TABLE 2 Signal Width I/O Description CWS active 1 I Medium Busyindicating a CWS RF activity 0 = idle/1 = active CWS Tx/Rx 1 I CWStraffic direction 0 = RX/1 = Tx CWS Priority 2 I CWS Priority 0 = Lowpriority/1 = BT high priority/2 = WLAN high priority (PS-POLL, ACK,BACK)/3 = reserved LTE active 1 O CWS-Kill indication

The RT interface may for example include the protocol synchronizationsignals as shown in table 3.

TABLE 3 SRC/ Signal Width Dest I/O Description LTE 1 CWS OSynchronization signal indicating LTE frame frame start sync UL gap 1CWS O Synchronization signal indicating LTE envelop UL gap. Envelopsignal with edges occurring 1 ms before in-the-air gar (raising andfalling edges) DL gap 1 CWS O Synchronization signal indicating LTEenvelop DL gap. Envelop signal with raising edge used only for LTE-TDD.Envelop signal with edges occurring 1 ms before in-the- air gar (raisingand falling edges)

In the following an example for a hardware implementation of the RTinterface between the first transceiver 1014 and the second transceiver1018 is given.

The example describes the RT interface between first communication chip1022 and the connectivity chip 1024. The purpose of the RT interface isto allow fast communication between both chips 1022, 1024 in bothdirections. Non-real time communication may for example be handled via astandardized interface between the first transceiver 1014 and the secondtransceiver 1018.

The real-time interface may be seen to basically consist of a set ofdiscrete signals as shown in FIG. 18.

FIG. 18 shows a communication circuit 1800 according to an aspect ofthis disclosure.

The communication circuit 1800 for example corresponds to the firstcommunication circuit 1022.

The communication circuit 1800 includes an LTE subsystem 1801 (L1CC)which may control all hardware interaction. The communication circuit1800 includes an RT interface 1803 via which the LTE subsystem 1801 maybe connected to another communication circuit, e.g. the secondcommunication circuit 1024, using various IDC (in device coexistence)signals which are indicated on the left hand side of the RT interface1803 and which are described in more detail in the following text.

According to one aspect of this disclosure, there are no specificrequirements on the electrical characteristics of the RT interface 1803.The IDC signals are for example configured during system startup. Thereis no need to reconfigure the IDC ports (implementing the RT interface1803) during operation.

From a hardware point of view the communication protocol on theinterface signals may be kept simple. However additional hardwaresupport may be required in the layer 1 subsystem context to support thereal time handling of the interface signals (i.e. the IDC signals).

The LTE subsystem 1801 includes an RT coex (coexistence) timer unit 1804which is responsible to generate time accurate events on the outputsignals IDC_LteDrxEnv, IDC_LteDtxEnv and IDC_LteFrameSync if configuredas output signal. If IDC_LteFrameSync is configured as input signal asnapshot of the LTE timing is taken. In the following the signalcharacteristics are described in more detail.

IDC_LteFrameSync-LTE2CWS_SYNC configuration (output signal):

This signal can be used to generate frame periodic pulses for the CWS1018. It should be noted that the pulse signal may not be availableduring LTE sleep phases.

IDC_LteDrxEnv, IDC_LteDtxEnv:

These output signals are envelope signals to indicate discontinuoustransmit/receive phases towards the CWS subsystem 1018. They are used toindicate discontinuous transmit/receive phases whichever their rootcause: DRX, DTX, measurements or any other. Both signals can beprogrammed individually via a timer.

IDC_LteFrameSync-CWS2LTE_SYNC configuration (input signal):

This signal may be used, LTE2CWS_SYNC may be desirable as solution whilethis one is kept as a fallback. Via this signal the CWS subsystem 1018can request a snapshot of the LTE timing. In addition an interrupt canbe generated on this event.

The LTE subsystem 1801 further includes an arbitration unit 1805, aninterrupt control unit (IRQ) 1806 and an LTE transmission (Tx) path1807. The arbitration unit 1805 is shown in more detail in FIG. 19.

FIG. 19 shows an arbitration unit 1900 according to an aspect of thisdisclosure.

The arbitration unit 1900 includes an IDC status register 1901, anarbitration look up table (LUT) 1902 and registers 1903.

The arbitration unit 1900 may serve for status indication (e.g. by meansof the IDC status register 1901) and for interrupt generation. Forexample, the current level of signals, e.g. the IDC related signalsmentioned in the following can be monitored via the arbitration unit1900. In addition some of the signals may be supplied to the interruptcontrol unit 1806.

The arbitration unit 1900 in its role as arbitration unit provideshardware support for the IDC real time arbitration. The task of thearbitration unit 1900 is to control the signals IDC_LteActive andIDC_LteKill depending on the input signals IDC_CwsActive, IDC_CwsTxRx,and IDC_CwsPriority (which can because of its width be seen to consistof two signals, IDC_CwsPriority1 and IDC_CwdPriority2). For this purposea combination of the input signals is done according to a programmablelookup table, the arbitration LUT 1902. The lookup table 1902 can beprogrammed on-the-fly via the LTE subsystem 1801.

IDC_LteActive: This signal is available at the IDC RT interface 1803.The connectivity chip 1024 is receiver of this signal. This signal maybe composed by hardware to provide a fast response in case of changinginput parameters. For example, the reset and isolation level of thissignal is zero.

IDC_LteKill: This signal can be used for an “ad-hoc” termination of anLTE transmission. Within the LTE subsystem 1014 the signal can be usedto generate an interrupt for the LTE subsystem 1804 and/or the LTE Txpath 1807. In principle this signal can be used for a directmanipulation of the Tx IQ data stream. For fallback purposes the LteKillsignal is visible at the external IDC real time interface 1803. Ifneeded the LteKill signal can be connected from the RT interface 1803 toa GPIO (General Purpose Input/Output) in order to enable a fast killingof a current LTE transmission.

The arbitration LUT 1902 may include dedicated lookup tables implementedfor IDC_LteActive and IDC_LteKill.

The arbitration unit 1900 may include filters 1904 for output signalfiltering. In principle transients on the output signals (e.g.IDC_LteActive and IDC_LteKill) are possible if e.g. an input signalchanges and/or the lookup table 1902 is updated. In case that thetransients cause a problem on the receiving side a filtering at theoutput might be required. In this case changes at the output onlyapplies if the inputs are stable for a minimum time (e.g. 1 μs). A 1 μsfiltering does not imply any loss of granularity in the signalingprocess as there is no need to indicate events shorter than 1 μs. Thisfiltering generates a 1 μs latency that can be hidden in requiring theCWS 1018 to indicate its activity on the RT interface 1030 1 μs earlier.

LTE-kill is a mechanism used to stop (or terminate) a current LTEtransmission (i.e. an UL communication) such that the LTE transceiver1014 does not transmit, e.g. in order to release the communicationmedium for WLAN/BT usage. It may for example occur as a result of realtime arbitration in favor of WLAN/BT.

According to one aspect of this disclosure, abrupt switch off of the LTEtransmission is avoided as it would have several side effects such asspurious emissions and possibly impacts on eNodeB AGC, power control.

In order to avoid these spurious, the LTE-kill may performed via a powerdecrease command (e.g. sent over a digRF interface) or via zeroing ofthe IQ samples. Usage of the power decrease command may be chosen over apower off command as it provides the possibility to reduce the LTEtransmit power down to −40 dBm (vs −50 dBm) while avoiding non-desirableside effects (such as PLL (Phase Locked Loop) shut down . . . ).

Using a command sent over a digRF interface ensure that variations oftransmit power are applied in a smooth manner hence avoiding spursgeneration.

According to one aspect of this disclosure, in order to adapt optimallyto the WLAN/BT traffic, the LTE-kill has a very short latency, e.g.approximately 10 μs for WLAN traffic and approximately 150 μs for BTtraffic.

FIG. 20 shows a transmission diagram 2000.

Along a timeline 2001, WLAN traffic over the medium is shown whereindata reception (i.e. downlink communication) is shown above the timeline2001 and data transmission (i.e. uplink communication) is shown belowthe timeline 2002. Further, LTE transmission for a first case 2002 andfor a second case 2003 are shown. Additionally, the CWS Rx/Tx over theRT interface 2004 is shown.

It should be noted that WLAN activity has a timing uncertainty due tocontention in CSMA (Carrier Sense Multiple Access):

-   -   if a WLAN device wins the access, timing uncertainty is in order        of several μs. It cannot be known precisely in advance but it is        bounded by WLAN MAC (Medium Access Control) protocol;    -   if a WLAN device loses the medium access, its activity is        differed by several hundreds of μs and can be considered from        the coexistence point of view as new traffic event. This cannot        be known in advance, and may repeat several times.

On the contrary, BT has no timing uncertainty.

It should be noted that it may be crucial to ensure that LTE-kill doesnot apply on consecutive retransmission of the same sub frame to protectthe HARQ. For FDD that means that LTE-kill of sub frames n and n+8 isforbidden. For this, a pattern to protect the HARQ channel may be used.

It should further be noted that full usage by the WLAN/BT of theremaining time in the killed LTE sub frame may be desirable.

In the following, another example for components of the communicationterminal 1000 is given.

FIG. 21 shows a communication terminal 2100.

The communication terminal 2100 for example corresponds to thecommunication terminal 1000 wherein only some of the components areshown while the others are omitted for simplicity.

The communication terminal 2100 includes an LTE subsystem 2101 forexample corresponding to the first transceiver 1014 and/or the LTEsubsystem 1801 and a WLAN/Bluetooth communication circuit 2102 forexample corresponding to the second communication circuit 1024. The LTEsubsystem 2101 copmrises an LTE radio module 2103 and a communicationcircuit 2104 for example corresponding to the first communicationcircuit 1022. The LTE subsystem 2101 may implement the L1 (layer 1) LTEcommunication stack 2114 and the LTE protocol stack 2115 (above layer1).

The communication terminal 2100 further includes an applicationprocessor 2105 for example corresponding to the processor (CPU) 1002.Connectivity applications 2112 (including WLAN applications and/orBluetooth applications) and LTE applications 2113 may run on theapplication processor 2105.

The communication circuit 2104 may include an NRT apps (applications)coexistence interface 2106 for communicating with the applicationprocessor 2105 by means of an application interface 2109 of theapplication processor 2105 and an NRT coexistence interface 2107 whichfor example corresponds to the NRT interface 1028 for communicating withthe WLAN/BT communication circuit 2102 by means of an NRT coexistenceinterface 2110 of the WLAN/BT communication circuit 2102 which forexample corresponds to the NRT interface 1032.

The LTE subsystem 2101 includes an RT arbitration entity 2111 (forexample corresponding to the arbitration unit 1805).

The communication circuit 2104 further includes an (LTE-connectivity)NRT arbitration entity 2108. It should be noted that the NRT arbitrationentity 2108 is not necessarily located in the communication circuit 2104but may also be located in other components of the communicationterminal 1000, 2108. It may for example be realized by the CPU 1002.

The LTE subsystem 2101 includes a first RT interface 2106 for examplecorresponding to the first RT interface 1026 and the WLAN/Bluetoothcommunication circuit 2102 includes a second RT interface 2107 forexample corresponding to the second RT interface 1030 which can be seento together form an RT interface 2116 between the LTE subsystem 2101 andthe WLAN/Bluetooth communication circuit 2102.

Table 4 shows the signals which may for example be exchanged over the RTinterface 2116.

TABLE 4 Used for in Used for in FDD TDD Signal Width I/O DescriptionBand 7 Band 40 CWS 1 I Medium Busy indicating a arbitration arbitrationactive CWS RF activity 0 = idle/1 = active CWS 1 I CWS traffic directionUnused (CWS arbitration Tx/Rx 0 = Rx active high 1 = Tx only for Rx) CWS2 I CWS Priority arbitration arbitration Priority 0: Low prio/1: BT highprio/2: WLAN high prio (PS-POLL, ACK, BACK)/3: reserved LTE 1 O CWS-Killindication arbitration arbitration active LTE 1 O Synchro signalindicating Unused Traffic frame LTE frame start synchronization sync ULgap 1 O Synchro signal indicating Traffic Traffic envelop LTE UL gap.Envelop synchronization synchronization signal with edges occurring 1 msbefore in- the-air gap (rising and falling edges) DL gap 1 O Synchrosignal indicating Unused Traffic envelop LTE DL gap. Envelopsynchronization signal with raising edge Used only for LTE- TDD. Envelopsignal with edges occurring 1 ms before in-the-air gap (raising andfalling edges)

It should be noted that the CWS priority signal can be seen as twosignals CWS priority 1 & 2 because of its width.

It should further be noted that the first transceiver 1014 and thesecond transceiver 1018 may also be connected via the applicationprocessor 2105 (i.e., for example, the CPU 1002) instead of a directconnection (as a direct RT interface). Further, it should be noted thatin general, communication may also be implemented via a serial orparallel bus instead of using dedicated signals (as for example shown intable 4).

According to one aspect of this disclosure, a degraded RT mode may beused. Specifically, only a subset of the RT coexistence I/F signals asgiven in table 4 may be effectively connected to the WLAN/Bluetoothcommunication circuit 2102.

For a FDD only platform (i.e. in case the first transceiver 1014 and thesecond transceiver 1018 only use FDD), a first option (referred to asoption 1a in table 5 below) for a degraded RT interface is to remove theDL gap envelop signal and the CWS Tx/Rx signal such that six signalsremain. Since these removed signals are useless for FDD, there is noimpact on the coexistence performance. As a second option (referred toas option 1b in table 5 below), in addition to the removal of the DL gapenvelop signal and the CWS Tx/Rx signal the CWS priority signal (CWSpriority signal 1 & 2) may be removed such that four signals remain. Inthis case, there is no more priority indication. Alternatively, a lightarbitration may be used where the second transceiver 1018 may indicateactivity only for high priority traffic, but high priority traffics fromBT and WLAN cannot be differentiated from each other.

For a FDD-TDD platform (i.e. in case the first transceiver 1014 and thesecond transceiver 1018 use both TDD and FDD), a first option (referredto as option 2 in table 5 below) is to get rid of arbitration and relysolely on traffic synchronization such that only three signals remain.In this case, the second transceiver 1018 becomes a pure slave and canonly use the communication resources left available by the LTEcommunication (i.e. the first transceiver 1014) and signaled via the DLgap envelop signal and the UL gap envelop signal or synchronization overthe TDD frame structure based on the LTE frame sync signal. In thiscase, there is no way to protect LTE traffic from wrong or too late CWSscheduling.

As a second option (referred to as option 3 in table 5 below), trafficsynchronization and light arbitration may kept such that six signalsremain. In this case, there are no priority settings. The secondtransceiver 1018 may only signal above a certain priority but may notdifferentiate between BT and WLAN. The same arbitration rules are usedfor the LTE-BT conflict and the LTE-WLAN conflict.

Table 5 summarizes the options for a degraded RT interface.

TABLE 5 Applicable Impact for TDD/ Removed I/F On Option FDD signalssignals BT WLAN LTE Comment 1a FDD only DL gap 6 None None None Trafficenvelop sync CWS Tx/Rx Arbitration 1b FDD only DL gap 4 None None Nbr ofTraffic envelop LTE sync CWS Tx/Rx denial Arbitration CWS Priorityincreased No 1 & 2 differentiation between WLAN and BT activity 2 FDD &CWS Active 3 HFP Use cases None Traffic TDD Cws Tx/Rx not supported synconly Cws Priority 1 supported only for No & 2 A2DP low/mediumarbitration LTE Active supported LTE air only occupancy for low/ mediumLTE air occupancy 3 FDD & Cws Priority 1 6 None None Nbr of Traffic TDD& 2 LTE sync denial Arbitration increased No differentiation betweenWLAN and BT activity

As a summary, the following may for example be provided for an RTcoexistence mechanism according to various aspects of this disclosure

-   -   LTE frame indication (signal+frame structure message)    -   UL gap indication    -   DL gap indication    -   Arbitration including short conflict possibility    -   HARQ protection (for arbitration and for LTE denial)    -   Degraded RT modes    -   Full usage of an LTE-killed subframe    -   Implementation of an RT interface as for example described above

General Coexistence Architecture

According to an aspect of this disclosure, five entities handle theLTE-CWS coexistence management: the NRT arbitration entity 2108, the NRTapplications coexistence interface 2106, the NRT coexistence interface(formed by NRT coexistence interfaces 2107, 2110), the RT arbitrationentity 2111 and the RT coexistence interface (formed by RT interfaces2106, 2107).

The (LTE-connectivity) NRT arbitration entity 2108 may for example beimplemented by software located in the communication circuit 2104. Forexample, it uses a mixture of application requirements (fromconnectivity and LTE apps) and context information from both cores (e.g.from both the first transceiver 1014 and the second transceiver 1018),e.g. the band, the bandwidth, the EARFCN (E-UTRA Absolute RadioFrequency Channel Number), to arbitrate and indicate static informationsuch as selected frequency bands or selected power levels to the firsttransceiver 1014 and the second transceiver 1018. It also providesindications to the RT arbiter 2111 located in the LTE subsystem 2101. Itshould be noted that according to one aspect of this disclosure, the NRTarbitration entity 2108 does not arbitrate between WLAN and BT. Thisarbitration may for example be performed in the WLAN/BT communicationcircuit.

The NRT apps (applications) coexistence interface 2106 may also be anentity implemented by means of software running on the communicationcircuit 2104. It transfers NRT messages carrying application informationfrom connectivity applications 2112 and LTE applications 2113 running onthe applications processor 2105. Table 6 gives a list of messages whichmay be exchanged between the application processor 2105 and thecommunication circuit 2104 by means of the NRT apps coexistenceinterface 2106 (and the corresponding application interface 2109).

TABLE 6 Messaging over LTE - NRT Apps coex I/F (R/W) Info ID Messagepayloads bits I/O Description 1 IS_COEX 1 I 1 = coexisting between atleast 2 systems 0 = no coexistence 2 IS_TETHERING 1 I 1 = WLAN entity isan Access Point 0 = WLAN entity is a STA 3 WLAN_APP_PERIOD 16 I Requiredservice period for WLANin ms 4 WLAN_APP_DURATION 6 I Required serviceduration for WLAN in ms 5 BT_APP_PERIOD 16 I Required service period forBT in ms. Applies for link using eSCO or SCO. 6 BT_APP_DURATION 6 IRequired service duration for BT in ms. Applies for link using eSCO orSCO only. 7 WLAN_APP_THROUGHPUT 16 I In kbps 8 BT_PROFILE_BITMAP 32 IBitmap of the active BT profiles (HFP, HSP, A2DP . . . ) 9LTE_APP_THROUGHPUT 16 I Application latency in ms 10 LTE_APP_LATENCY 16I In kbps

The NRT coexistence interface 2107 may also be an entity implemented bySW located in the communication circuit 2104. It transfers NRT messagescarrying context information from the WLAN/BT communication circuit andsends notifications from the NRT arbiter 2108 to the WLAN/BTcommunication circuit (by means of the corresponding NRT coexistenceinterface 2110 of the WLAN/BT communication circuit). Table 7 gives alist of messages that may for example be exchanged over the interfaceformed by the NRT coexistence interface 2107 of the communicationcircuit 2104 and the NRT coexistence interface 2110 of the WLAN/BTcommunication circuit 2102.

TABLE 7 Messaging over LTE - NRT coex I/F (R/W) Info ID Message payloadsbits I/O Description 1 WLAN_CHAN_NBR 3 I/O WLAN channel number (appliedor to be applied) 2 WLAN_BW 1 I/O WLAN bandwidth (applied or to beapplied): 0 = 20 Mhz 1 = 40 Mhz 3 WLAN_MCS 4 I WLAN MCS 4 WLAN_TX_POWER4 I/O WLAN Tx power (applied or to be applied) 5 WLAN_CHANNEL_RANK 14 ×4 I WLAN channel map ranked from preferred to worst based on SINRmeasurements and WLAN/BT constraints 6 BT_AFH_RANK 79 × 3 I Full AFH map(including channels that could be excluded for WLAN/BT coex) withpreference coded over 3 bits: 000 ->preferred 111 ->worst 7 BT_AFH_MAP79 I/O BT AFH bitmap (applied or to be applied) 8 BT_PKT_TYPE 4 IBluetooth packet type 9 GNSS_BD 2 Operating frequency band 10 GNSS_STATE2 0 = sleep 1 = acquisition 2 = tracking 11 LTE_BITMAP 10 × 2 O 0 =Special subframe 1 = RX LTE subframe 2 = TX LTE subframe 13 WLAN_LTE_EN1 O Transmission of WLAN packets shorter than wlan_short_tx during LTERX allowed 14 BT_LTE_EN 1 O Transmission of BT packets at power <bt_low_pwr_tx during LTE RX allowed 15 LTE_SPS_PATTERN 24 O SPSPeriodicity (ms): 11 bits SPS event duration (ms): 9 bits SPS initialoffset (sub-frame offset in first LTE frame where SPS is applied): 4bits

It should be noted that the LTE bitmap can be changed (limited to sevenframe structures but also more configurations for the S content itself).It should further be noted that the NRT messages mentioned above canalso be sent partially or in totality to the eNodeB 103 if some decisionrelative to coexistence are taken by it.

Additionally, it should be noted that depending on the platformarchitecture and application stacks, the split between informationlocated in the communication circuit 2104 and in the WLAN/BTcommunication circuit 2102 may change.

According to one aspect of this disclosure, the NRT coexistencealgorithm and the RT coexistence algorithm are coordinated. This isillustrated in FIG. 22.

FIG. 22 shows a flow diagram 2200.

When the coexistence status changes within the communication terminal1000 in 2201, the NRT coexistence mechanisms are activated in 2202.Messaging is then sent over the NRT coexistence interface to apply theNRT arbitration decisions.

Consecutively, in 2203, the de-sensing level for the connectivity RATreached with the newly applied NRT arbitration is estimated usingpre-calculated RF interference tables. If it is above the desensetarget, the RT coexistence mechanisms are enabled 2204 and they runcontinuously in an autonomous manner. If the de-sensing level is belowthe desense target, in 2205, the RT coexistence mechanisms are disabled.

When receiving updates (via SW messages) either from the LTE subsystem2101 or the WLAN/BT communication circuit 2102, the NRT arbiter 2108 candetect a change of the coexistence status, in the sense that, forexample, if the frequency used for LTE and CWS communication so far werenot in the critical bands, it could now have become the case andcoexistence algorithms need to be activated.

The NRT arbiter 2108 is the responsible entity for activating ordeactivating any specific coexistence algorithm, and is always ready toreceive input messages from LTE or CWS indicating change in any of therelevant parameters.

Cases of coexistence status change may for example include (amongothers):

-   -   a second RAT becomes active;    -   a handover is performed in LTE communication to another LTE        band;    -   the LTE bandwidth is modified;    -   the number of active RATs go down to 1.

As described above, according to various aspects of this disclosure,there may be a split (e.g. in terms of interfaces) between RT and NRT.RT and NRT processing may be synchronized. NRT messaging may be extendedby messaging between the communication terminal 105 and the eNodeB 103.

NRT Coexistence Mechanisms

The NRT coexistence mechanism may include an FDM/PC (Frequency DivisionMultiplex/Power Control) algorithm for Bluetooth which is described inthe following.

Bluetooth medium access is based on a slotted traffic scheduling. Slotsare scheduled in time and frequency on a fixed grid. The time slots are625 μs long and are mapped onto 1 Mhz wide BT channels. The frequencychannel used for a given timeslot is imposed by the frequency hoppingpattern, it pseudo randomly changes from slot to slot.

A BT entity (e.g. in form of the communication terminal 1000 usingBluetooth) can be either a (Bluetooth) Master or a (Bluetooth) Slave. ABluetooth master provides reference time and controls the synchronismand the activity of a piconet that is controls which is a small networkof Bluetooth devices surrounding it. Slave entities have to monitorperiodically the medium to capture any control information coming fromthe piconet master. A Bluetooth slave listens on all potential mastertransmissions (1.25 ms period) during a slot or a slot fraction andanswers in next slot if it has received a packet addressed to it in thecurrent slot. A BT slave can use “Sniff mode” to lower power consumptionand avoid: master-slave transaction only on reserved slots (negotiatedbefore going into sniff mode).

According to Bluetooth, useful data and/or control data is carried overtwo periodic and/or asynchronous packets. The kind of packets used for agiven data traffic depends on the corresponding traffic profile (whichis standardized). Control traffic is carried by asynchronous traffic.

A BT slave can use “Sniff mode” to lower power consumption and avoid:master-slave transaction only on reserved slots (negotiated before goinginto sniff mode).

Target Bluetooth profiles may be A2DP for audio (e.g. music) streamingand HFP as voice headset profile. A2DP is an asynchronous trafficprofile using variable length packets (single-multislot), HFP is aperiodic single slot traffic transferred in scheduled (reserved) slots.Devices may also be BTpaired with no traffic.

Slots may be reserved during link set-up (by Link Managers). Most commonpackets are HV3 packets (for Synchronous Connection-Oriented (SCO)communication), which occupy one third of the double slots.

An example for Multi slot Bluetooth traffic is illustrated in FIG. 23.

FIG. 23 shows a transmission diagram 2300.

In the transmission diagram 2300, time increases from left to right andis divided into time slots 2301 of 625 μs. First transmissions 2302 areperformed by a master device and second transmissions 2303 are performedby a slave device.

Bluetooth communication applies frequency hopping. In a communication,the operating frequency channel changes pseudo-randomly from time slotto time slot and performs a pseudo random walk through 79 available 1Mhz channels in the ISM band 202.

Adaptive frequency hopping (AFH) is a mechanism which allows limitingthis to a subset of the 79 channels. The number N of used channels musthowever not go below 20. The channel map selection is completelyflexible but results from a negotiation between master and slaveperformed on a static basis. AFH can be disabled for parked slaves.

The adaptive frequency hopping mechanism may be used to push away the BTtraffic from the LTE frequency bands. It is especially efficient toprotect LTE Rx from BT Tx (LTE-TDD case), less in the reverse directionbecause BT front end (filter/low noise amplifier (LNA)) is wide band.

According to one aspect of this disclosure, the adaptive frequencyhopping mechanism is exploited by the following:

-   -   The first communication circuit 1022 performs static requests to        the second communication circuit 1024 (acting as (local) BT        core) to modify its channel map;    -   The second communication circuit 1024 updates the channel map        and aligns it with the peer entity (e.g. another communication        terminal);

The Bluetooth spectrum occupancy can be reduced down to one third of theISM band 202. This provides a guard band of up to 60 Mhz to LTE-Band 40201 and a guard band of up to 79 Mhz to LTE-Band 7 UL 204. It should benoted that the efficiency of AFH for BT/LTE coexistence may be limiteddue to the fact that the BT RX front end receives the full band even inAFH context (non-linearities are there anyway).

The impact of the usage of this mechanism on BT/WLAN coexistence can beseen to be limited.

In the following, an procedure for protecting Bluetooth from LTE-FDDtransmissions in LTE-Band 7 UL 204 is described with reference to FIG.24.

FIG. 24 shows a message flow diagram 2400.

An NRT algorithm corresponding to the message flow diagram 2400 may forexample be carried out by the NRT arbitration unit 2108.

The message flow takes place between a LTE subsystem 2401 correspondingto the LTE subsystem 2101 (e.g. corresponding software), an NRT arbiter2402 corresponding to the NRT arbiter 2108 and a BT communicationcircuit 2403 corresponding to the WLAN/BT communication circuit 2102.

In 2404, the NRT arbiter 2402 loads the BT desensing target.

In 2405, the NRT arbiter 2402 sends an LTE info request message 2406 tothe LTE subsystem 2401 for requesting information about the LTEconfiguration.

In 2407, the LTE subsystem 2401 generates information about the LTEconfiguration, e.g. an LTE information table including the band used,the bandwidth used, the EARFCN, the path loss margin (estimatedtransmission power decrease without triggering modulation/bandwidthchange) etc.

In 2408, the LTE subsystem 2401 sends the generated information with anLTE information confirm message 2409 to the NRT arbiter 2402.

In 2410, the NRT arbiter 2042 stores the information received with theLTE information confirm message 2409.

In 2411, the NRT arbiter 2402 sends an AFH map request message 2412 tothe BT communication circuit 2403 for requesting an AFH map.

In 2413, the BT communication circuit 2403 builds a ranked AFH mapincluding channels excluded for coexistence.

In 2414, the BT communication circuit 2403 sends the generated AFH mapto the NRT arbiter 2402 with an AFH map confirm message 2415.

In 2416, the NRT arbiter 2402 generates a new AFH map. The target inthis is the BT de-sensing level. The generation may for example includethe following:

1) Calculate delta F for BT channels (full band, granularity to bedefined)2) Evaluate BT de-sensing vs operated BT channels (full band) usingisolation table (static, pre-calculated for LTE at full power)3) Select N, highest number of BT channels satisfying BT de-sensingtarget4) If target cannot be achieved or N<Nmin then use Nmin5) If target cannot be achieved keeping exclusion applied for WLAN/BTcoex->neglict

6) Build new AFH map

In 2417, the NRT arbiter 2402 sends the new AFH map to the BTcommunication circuit 2403 with an AFH set request message 2418requesting the BT communication circuit 2403 to use the new AFH map.

In 2419, the BT communication circuit 2403 updates the frequency hoppingsequence accordingly.

In 2420, the BT communication circuit 2403 confirms the usage of the newAFH map by means of an AFH set confirm message 2421.

In 2422, the NRT arbiter 2402 selects the highest LTE Tx (transmission)power satisfying the BT de-sensing target and the LTE Tx pathlossmargin.

It should be noted that this approach may be dangerous forinteroperability tests (IOT). According to one aspect of thisdisclosure, it is ensured that it is applied only in the coexistencecase as defined by AP.

In 2423, the NRT arbiter 2402 sends the determined LTE Tx power to theLTE subsystem 2401 with a power request message 2424 requesting the LTEsubsystem 2401 to use the determined Tx power.

In 2425, the LTE subsystem 2401 applies the Tx power accordingly.

In 2426, the LTE subsystem 2401 confirms the usage of the Tx power bymeans of a power confirm message 2427.

It is assumed that in 2428, the NRT arbiter 2402 realizes that no morecoexistence is to care of from now.

In 2429, the NRT arbiter 2402 sends a cancel power request message 2430to the LTE subsystem 2401 which is confirmed in 2431 by means of acancel power confirm message 2432 from the LTE subsystem 2401.

According to one aspect of this disclosure, the NRT coexistencemechanism includes an FDM/PC algorithm for WLAN which is described inthe following.

WLAN medium access is based on Carrier Sense Medium Access (CSMA) wherestations listen to the medium and compete to get access to it when it isfree. There is no resource scheduling, no traffic periodicity. A globalsynchronization is achieved via a beacon transmitted every approximately102 ms by the access point but effective beacon transmission can bedelayed due to medium occupancy.

WLAN MAC adapts to the radio channel conditions via a link rateadaptation, based on packet error rate computed at transmitter sidebased on received ACKs (positive ACK with retransmission).

In the 2.4 Ghz band (ISM band), WLAN systems operate over 14 overlappingchannels referred to as CH #1 to CH#14 (CH #14 is used only in Japan).This is illustrated in FIG. 25.

FIG. 25 shows a frequency allocation diagram 2500.

In the frequency allocation diagram 2500, frequency increases from leftto right. The 14 overlapping channels allocated for WLAN are illustratedby half circles 2501.

WLAN is typically operating in BSS (basic service set) mode. Peer topeer mode also exists but is rarely used yet. However, it may becomeuseful in the smartphone use case.

In BSS mode, the access point (AP) has full control of the operated WLANchannel selection and mobile station (STA). The WLAN channel is selectedin a static access point.

According to one aspect of this disclosure, WLAN power control is usedfor reducing interference to LTE communication.

WLAN has a peak power of approximately 20 dBm, and is usuallytransmitting at full power to enable the highest possible PHY rate andshorten as much as possible the packet duration for power consumptionreasons. However, the WLAN protocol stack does not prevent from using alower Tx power nor define a rule to select the used power.

If needed, the second transceiver 1018 (operating as WLAN transceiver inthis example) embedded in the communication terminal 1000 canautonomously reduce its Tx power:

-   -   If the communication terminal 1000 acts by means of the second        transceiver 1018 as a station connected to a home access point        or a hot spot, this is likely to trigger a link rate adaptation        event to downgrade PHY rate which would cause higher packet        duration and hence longer interference from WLAN to LTE.        According to one aspect of this disclosure, usage of power        control is limited in that case.    -   If the communication terminal 1000 acts by means of the second        transceiver 1018 as an AP (i.e. tethering case) the distance        between the communication terminal 1000 (for example a        smartphone) used as an access point (router) and a connected        WLAN (e.g. Wifi) client (e.g. laptop) is under control of the        user and can be made close. The communication terminal 1000 can        then reduce significantly its WLAN Tx power to balance the lower        BSS coverage and associated pathloss.

A comparison of the estimated path loss for tethering vs hot spot isgiven in table 8.

TABLE 8 Use case Tethering Hot spot (indoor) AP-STA distance 10 30Pathloss_dB 66.1 85.2 Delta_dB 19.1

The rough estimation as given in table 8 gives a 19 dB margin betweenhot spot and tethering showing that the WLAN Tx power can be reduced byup to 19 dB which corresponds to 1 dBm.

According to one aspect of this disclosure, the AP Tx power is reducedgradually and the PER evolution at the AP is monitored (PER statisticsare always build in WLAN).

In summary, WLAN power control could bring a 15-20 dB reduction of WLANto LTE interference in case of tethering. LTE to WLAN interferencerejection requirements could be relaxed (WLAN de-sensing requirement).This approach may not be suitable if coupled with TDM (Time DivisionMultiplex) solutions as Tx power reduction may lead to lower phy rateand thus increased Tx duration. There may be a trade-off between powercontrol and high PHY rates usage.

According to one aspect of this disclosure, WLAN channel selection isused for reducing WLAN/LTE interference.

In the use cases where the communication terminal 1000 (as WLAN entity)acts as an AP (e.g. for tethering) it can freely select the WLAN channelfor its operation. Therefore the WLAN traffic can be pushed away fromLTE operating band hence protecting both WLAN from LTE and LTE fromWLAN. According to one aspect of this disclosure, WLAN channel qualityas perceived by WLAN APs, e.g. reflecting channel occupation by a nearbyhot spot or home AP, are taken into account in this process.

WLAN channel selection can bring 18 to 42 dB rejection of WLAN to LTE(LTE-Band 40) interference when channels CH#3 to #14 are selected. Thismechanisms is compatible with power control solutions which can be usedon top.

WLAN channel selection can bring 27 to 77 dB rejection of LTE (LTE-Band40) to WLAN interference when channels CH#3 to #10 are selected.

Altogether, AP channel selection can reduce

-   -   WLAN to LTE-Band 40 OOB (out-of-band) rejection by 18 to 42 dB    -   LTE-Band 40 to WLAN OOB rejection by 27 to 77 dB    -   LTE-Band 7 UL->WLAN OOB rejection by 19 to 49 dB

This mechanism does not harm the WLAN throughput or robustness.

It should be noted that the aforementioned analysis takes into accountOOB noise effect only, hence assuming that the non line effects such assignal compression of reciprocal mixing have been avoided by RF systemdesign.

In the following, an procedure for protecting WLAN from LTE-FDDtransmissions in LTE-Band 7 UL 204 is described with reference to FIG.26.

FIG. 26 shows a message flow diagram 2600.

An NRT algorithm corresponding to the message flow diagram 2600 may forexample be carried out by the NRT arbitration unit 2108.

The message flow takes place between a LTE subsystem 2601 correspondingto the LTE subsystem 2101 (e.g. corresponding software), an NRT arbiter2602 corresponding to the NRT arbiter 2108 and a WLAN communicationcircuit 2603 corresponding to the WLAN/BT communication circuit 2102.

In 2604, the NRT arbiter 2602 loads the WLAN desensing target.

In 2605, the NRT arbiter 2602 sends an LTE info request message 2606 tothe LTE subsystem 2601 for requesting information about the LTEconfiguration.

In 2607, the LTE subsystem 2601 generates information about the LTEconfiguration, e.g. an LTE information table including the band used,the bandwidth used, the EARFCN, the path loss margin (estimatedtransmission power decrease without triggering modulation/bandwidthchange) etc.

In 2608, the LTE subsystem 2601 sends the generated information with anLTE information confirm message 2609 to the NRT arbiter 2602.

In 2610, the NRT arbiter 2602 stores the information received with theLTE information confirm message 2608.

In 2611, the NRT arbiter 2602 sends an channel map request message 2612to the WLAN communication circuit 2603 for requesting an channel map.

In 2613, the WLAN communication circuit 2603 builds a ranked channel mapThe ranking may be based on SINR (signal to noise ratio) and WLAN/BTconstraints.

In 2614, the WLAN communication circuit 2603 sends the generated channelmap to the NRT arbiter 2602 with a channel map confirm message 2615.

In 2615, the NRT arbiter 2602 determines a WLAN channel to be used. Thetarget in this is the WLAN de-sensing level. The determination may forexample include the following:

1) Calculate delta F for each WLAN channel2) Evaluate WLAN de-sensing for each WLAN channel usage using isolationtable (static, pre-calculated for LTE at full power)3) Select highest ranked WLAN channel satisfying WLAN de-sensing target

In 2617, the NRT arbiter 2602 sends an indication of the determined WLANchannel to the WLAN communication circuit 2603 with an set channelrequest message 2618 requesting the WLAN communication circuit 2603 touse the determined WLAN channel.

In 2619, the WLAN communication circuit 2603 accordingly moves to thedetermined WLAN channel.

In 2620, the WLAN communication circuit 2603 confirms the usage of thedetermined WLAN channel by means of a set channel confirm message 2621.

In 2622, the NRT arbiter 2602 stores an indication of the WLAN channel.

In 2623, the NRT arbiter 2602 sends an WLAN info request message 2624 tothe WLAN communication circuit 2603 for requesting information about theWLAN configuration.

In 2625, the WLAN communication circuit 2603 generates information aboutthe WLAN configuration, e.g. a WLAN information table including thechannel number, the MCS (Modulation and Coding Scheme), the Tx poweretc.

In 2626, the WLAN communication circuit 2603 sends the generatedinformation with an WLAN information confirm message 2627 to the NRTarbiter 2602.

In 2628, the NRT arbiter 2602 selects the highest LTE Tx (transmission)power satisfying the WLAN de-sensing target and the LTE Tx pathlossmargin.

This may include the following:

1) Calculate delta F for the operated WLAN channel;2) Evaluate WLAN de-sensing for operated WLAN channel using isolationtable (static, pre-calculated for LTE at full power);3) Select highest LTE Tx power satisfying WLAN de-sensing target and LTETx pathloss margin

It should be noted that this approach may be dangerous forinteroperability testing (IOT). According to one aspect of thisdisclosure, it is ensured that it is applied only in the coexistencecase as defined by AP.

In 2629, the NRT arbiter 2602 sends the determined LTE Tx power to theLTE subsystem with a power request message 2630 requesting the LTEsubsystem 2601 to use the determined Tx power.

In 2631, the LTE subsystem 2601 applies the Tx power accordingly.

In 2632, the LTE subsystem 2601 confirms the usage of the Tx power bymeans of a power confirm message 2633.

It is assumed that in 2634, the NRT arbiter 2602 realizes that no morecoexistence is to care of from now.

In 2635, the NRT arbiter 2602 sends a cancel power request message 2636to the LTE subsystem 2601 which is confirmed in 2637 by means of acancel power confirm message 2638 from the LTE subsystem 2601.

Messages that may for example be exchanged over the NRT interface formedby the NRT coexistence interface 2107 of the communication circuit 2104and the NRT coexistence interface 2110 of the WLAN/BT communicationcircuit 2102 (e.g. operating as WLAN/BT baseband circuit) in the contextof NRT coexistence have been shown above in table 7. Further examplesare given in the following text.

According to one aspect of this disclosure measurement gap configurationin LTE connected Mode is used for LTE-WLAN coexistence.

While in LTE connected mode, measurement gaps are defined in 3GPPspecifications to enable single radio mobile terminals (i.e. mobileterminals with only one LTE transceiver which are not capable ofmeasuring transparently other frequencies (than the one used by theserving cell) while in LTE connected mode) to perform measurements of:

-   -   1. LTE neighbor cells operating on different frequencies than        the serving cell (inter-frequency measurements)    -   2. Other RAT (e.g. 2G or 3G) neighbor cells (inter-RAT        measurements).

Typically, when LTE is the serving RAT, those measurement gaps have aduration of 6 ms and are scheduled with either 40 ms or 80 msperiodicity.

If LTE communication is performed using a frequency that is interferingwith WLAN communication and vice-versa, the measurement gaps can be usedfor safe WLAN reception and transmission:

-   -   if the gap is used for an LTE inter-frequency measurement, and        if the LTE frequency if not overlapping with WLAN frequency    -   if the gap is used for 2G or 3G measurement, as there is no        interference possible between 2G/3G and the ISM frequency bands,        the gap can be used without restriction for WLAN/BT in parallel        to the LTE measurement.

Additionally, in LTE connected mode, for better closed subscriber group(CSG) cell support, 3GPP Release 9 introduces the concept of so calledautonomous measurement gaps. The reason here is that for CSG cells, theSIB (System Information Block) needs to be read which may requireadditional measurement gaps asynchronous to the ones scheduled in theregular intervals. If the network supports autonomous measurement gaps,the mobile terminal is allowed to ignore a few TTIs as long as themobile terminal is able to send at least 60 ACK/NAKs per 150 msinterval. The HARQ and higher layer signaling ensure that data does notget lost.

To inform in advance the second transceiver 1018 of any upcoming regulargap occurrence, during which no interference to WLAN reception ortransmission will occur, the first transceiver 1014 (e.g. the LTEbaseband circuit) can send a message to the second transceiver 1018(e.g. the CWS baseband circuit), indicating a gap pattern along with:

-   -   the measurement gap pattern periodicity (for example 40/80 ms),    -   the measurement gap duration (example 6 ms)    -   an unambiguous method to identify the first measurement gap        occurrence for the considered measurement gap pattern.

This may be used for:

-   -   interfrequency measurement gaps,    -   inter RAT measurement gaps,    -   autonomous measurement gaps.

The message can for example be a Periodic_Gap_Pattern_Config(periodicity, duration, first occurrence date) message, sent from thefirst transceiver 1014 (e.g. the LTE baseband circuit) to the secondtransceiver 1018 (e.g. the CWS baseband circuit) which indicatesperiodic gap pattern, and during each of those gaps the secondtransceiver 1018 can freely perform transmission and reception.

A criterion and decision in the first transceiver 1014 (e.g. the LTEbaseband circuit) to enable the sending of a gap message indication fromthe first transceiver 1014 (e.g. implementing an LTE Protocol Stack orLTE Physical Layer) controlled by the first processor to the secondtransceiver 1018 (e.g. the CWS baseband circuit) may belong to the NonReal Time (e.g. software) Arbiter 2108 entity which may run on the firsttransceiver 1014 (e.g. the LTE baseband circuit), based on whether:

-   -   frequency interference occurs;    -   there was enough or not enough interference free time periods        during which the second transceiver 1018 (e.g. the CWS baseband        circuit) could operate.

The gap message indication may be enabled or disabled dynamically by theNon Real Time (e.g. software) Arbiter 2108 whenever it considers thecriterion fulfilled to start or stop using gaps to insure proper secondtransceiver 1018 functionality.

In summary, WLAN communication can be protected from LTE Band 7 UL 204,Bluetooth communication can be protected from LTE Band 7 UL 204 and alsoWLAN communication can be protected from LTE Band 40 201 and Bluetoothcommunication can be protected from LTE Band 40 201.

PHY Mitigations

Pilot symbols in interfered OFDM symbols are typically meaningless. Asworst case the case may be seen that two consecutive OFDM symbols arelost per LTE slot. This means that one pilot is missing per antenna perslot (e.g. among two for antennas 0 and 1, among one for antennas 2 and3). It should be noted that antennas 0 and 1 are only relevant forsmartphone. It remains one (for ½ antennas) worst case: one pilot ismissing for a given carrier.

This may have the following impacts:

1) The outer receiver can be impacted on AGC, Noise estimation, channelestimation.

-   -   These tasks are processed with a delay which is sufficient to        exploit a real time indication of the WLAN interfering burst,    -   Some filters already exist in equalizer to compensate absence of        a RS (reference signal),    -   The indication of the WLAN interfering burst could be used by        outer receiver to declare the corresponding RS, if any, as        missing, an existing filter could be applied then,    -   This real time indication may be included in the RT coexistence        interface        In summary, outer receiver protection from WLAN short        interference can be done by framework modifications (the        implementation of the RT coexistence and RT arbitration can be        done as pre-requisite).        2) Inner receiver:    -   Transport block/code word/Code block vulnerability may be        difficult to evaluate; impact depends at least on code block        length and channel conditions:        -   In best case, code blocks are recovered by the turbo code,            such that there is no impact on LTE throughput        -   In worst case a code block is impacted similarly in            consecutive HARQ retransmissions (periodically). This would            mean that the corresponding transport block would never go            through the transmission.

It is typically desirable to avoid the worst case. Further, it may bedesirable to prevent two consecutive interfering burst in the same LTEsubframe. For example, this may be done by banning two consecutiveinterfering WLAN burst spaced by the HARQ period (e.g. 8 ms).

According to one aspect of this disclosure, spur nulling may be used toaddress the above issues which can be seen as a frequency domainsolution. It is for example assumed that the spur does not saturate theFFT (hence spilling over the full bandwidth in frequency domain): TheWLAN/BT requirements on transmission spurious emission may bedimensioned accordingly. For example, frequency domain spur detection &frequency domain spur nulling or signal spur nulling may be applied.

In summary, RS filtering based on an RT coexistence indication (AGC,noise estimation and channel estimation protection) and/or spurdetection and nulling is applied for coexistence.

Protocol Mitigations

On the LTE side, several protocol mechanisms may be used to preventconflicts between the LTE and WLAN/BT activities on the communicationmedium:

-   -   In absence of idle gaps or when their number/duration are        insufficient compared to the WLAN/BT needs, some techniques can        be used at protocol level to deny some LTE sub frames so that        they can be used by WLAN/BT. This is referred to as LTE denial.        Such techniques may not rely on current 3GPP specifications and        may be done autonomously at mobile terminal level. However they        may be partially included in 3GPP standard from Release 11 (IDC        Work Item).    -   Additionally, when the mobile terminal is in handover range, it        may try to influence the eUTRAN to prioritize handover towards        cell with coexistence-friendly carrier frequency. It can also        try to delay the handover toward a less coexistence-friendly        cell. This is also referred to as coexistence-friendly handover.

LTE denial can be implemented using UL-grant ignoring or SR(schedulerequest)-postponing. Coexistence-friendly handover can be implementedvia smart reporting of neighboring cells measurement results (valuesand/or timelines).

The impact of WLAN and Bluetooth use cases over LTE-FDD for fullconnectivity traffic support, relying only on LTE denial, is illustratedabove in FIGS. 16 and 17. This can be seen as the worst case for theLTE-FDD side and can be used as reference to quantify the enhancementprovided by coexistence mechanisms for LTE-FDD. The followingassumptions are made:

-   -   Systematic LTE denial    -   WLAN is operated with medium channel quality (29 Mbps PHY rate        worst case)    -   WLAN STA (i.e. Not valid for tethering).

Tables 9 and 10 further illustrate the worst case impact of Bluetoothuse cases over LTE-FDD and worst case impact of WLAN use cases overLTE-FDD (assuming full support, no LTE gaps), respectively. The usecases are the same as illustrated in FIGS. 16 and 17.

TABLE 9 Best case (w/o BT traffic profiles (from use cases) Worst case(w/o gap) gap) HFP bi-directional - master, SCO 4 non consecutive ULIdent HV3 - 64 Kbps + 64 Kbps sub-frame over 11 (36%) HFPbi-directional - master, eSCO In absence of Ident EV3 64 kbps + 64 kbpsre-transmission, 1 UL sub-frame over 6 (16.6%) A2DP SBC stereo HighQuality, SRC - 4 non consecutive UL Ident master, 2-DH5, 345 Kbps,period 30 ms sub-frame per 30 ms (13.3%)

TABLE 10 WLAN traffic types Best case (from use cases) Worst case (w/ogap) (w/o gap) WLAN Beacon listening 2 subframe denied every 300 msIdent ( 2/300) Skype video - 2 subframes every 20 ms ( 1/10) Identbidirectional 1 Mbps Youtube - DL 600 kbps 2 consecutive subframes Identevery 20 ms ( 1/10) TCP - DL 600 kbps 1 subframe every 20 ms ( 1/20)Ident

According to one aspect of this disclosure, LTE denial consist in:

-   -   Denying autonomously at mobile terminal level the usage of UL        sub-frames where LTE has allocated communication resources. This        can be applied to both LTE-FDD (e.g. LTE-Band 7 UL 204) and        LTE-TDD (e.g. LTE-Band 40 201),    -   Denying autonomously at mobile terminal level the usage of DL        sub-frames where LTE has allocated communication resources. This        can be applied to LTE-TDD (e.g. LTE-Band 40 201)

It should be noted that for UL denial a cancellation/postponing of thescheduled LTE activity may be done while for DL denial, allowingsimultaneous TX activity on the CWS side may be sufficient.

In context of SR postponing, it should be noted that LTE has beendesigned to address the need for mobile Internet access. Internettraffic can be characterized by a high burstiness with high peak datarates and long silence periods. In order to allow for battery savings,an LTE communication system (as shown in FIG. 1) allows for DRX. Two DRXprofiles are introduced addressed by short DRX and long DRX,respectively. For the reverse link, i.e. the uplink, in order toincrease system capacity, an LTE communication system allows fordiscontinuous transmission (DTX). For uplink traffic, the mobileterminal 105 reports its uplink buffer status to the eNB 103 which thenschedules and assigns uplink resource blocks (RBs) to the mobileterminal 105. In case of empty buffers, the eNB 103 may not schedule anyuplink capacity in which case the UE 105 is not able to report itsuplink buffer status. In case the uplink buffer changes in one of itsuplink queues, the UE 105 sends a so called schedule request (SR) to beable to report its buffer status in a subsequent scheduled uplink sharedchannel (PUSCH).

In order to prevent this from happening, the mobile terminal 105 MAClayer may delay the SR if the DTX period has been previously granted toWLAN activity. According to one aspect of this disclosure, thismechanism may be used for LTE/WLAN coexistence. It is illustrated inFIG. 27.

FIG. 27 shows a transmission diagram 2700.

LTE uplink transmissions are illustrated along a first timeline 2701 andLTE downlink transmissions are illustrated along a second timeline 2702.The transmissions for example occur between the mobile terminal 105 andthe base station 103 serving the mobile terminal 105. Time increasesfrom left to right along the time lines 2701, 2702.

In this example, the mobile terminal 105 receives an UL grant in a firstTTI 2703. The mobile terminal 105 responds to this UL grant by sendingan UL signal in a second TTI 2704. At the same time, the mobile terminal105 is setting its DRX inactivity timer. Assuming that no further ULgrants or DL transport blocks (TBs) have been scheduled which wouldcause the DRX inactivity timer to be reset to the DRX inactivity time,after the mobile terminal 105 receives the outstanding ACK of the lastUL transport block it sent (as illustrated by arrow 2705), DRX and DTXconditions are met. During the DRX and DTX period 2706, the mobileterminal 105 does not need to listen to any downlink control channels inthe PDCCH and the mobile terminal 105 not scheduled by the eNB 103before the end of the DRX and DTX period 2706. The DRX and DTX period2706 may be used for WLAN transfer.

The mobile terminal 105 may send an SR in case it requires sending someuplink data which would put an end to the DRX and DTX period 2706. Inorder to prevent this from happening, the mobile terminal MAC maysuppress the SR if the period is used for interfering WLAN activity.

In the example of FIG. 27, the mobile terminal 105 receives an UL grantin the first TTI 2703. The mobile terminal 105 complies with this ULgrant by sending an UL signal in the second TTI 2704 (four TTIs later).However, the mobile terminal 105 may ignore this UL grant hence denyingthe UL sub frame coming four TTIs later which is hence release forWLAN/BT operations. This released sub frame is indicated to the CWS chip1024 using the RT coexistence interface 1026 (UL gap indication).

According to one aspect of this disclosure, LTE denial with HARQprotection is used. This is described in the following.

In LTE-WLAN/BT coexistence, usage of LTE-denial may be required torelease a LTE subframe for connectivity traffic (overruling LTEsub-frame allocation). When applied in UL, LTE denial may be seen tocorresponds to preventing the LTE transceiver 1014 from transmitting ina sub-frame where it had some allocated communication resources. In thiscase, the characteristics of the LTE HARQ mechanism may be taken intoaccount: HARQ is a MAC level mechanism of retransmission which issynchronous and periodic with a 8 ms period (UL case, in DL it isasynchronous).

In LTE-FDD UL, HARQ is synchronous and supports a maximum of eightprocesses. The potential retransmission of a packet initiallytransmitted in sub-frame N hence occurs in sub-frames N+8*K, with K>=1.Thus, the impact of LTE-denial over a transport channel can differ a lotdepending on interaction with LTE HARQ. E.g. a periodic LTE-denial with8 ms period may impact every repetition attempt of a single HARQ processand may lead to a link loss. An example with a denial period of 12 ms isillustrated in FIG. 28.

FIG. 28 shows a transmission diagram 2800.

Along a first time line 2801, UL sub-frame denial and the allocation ofthe TTIs to HARQ processes (numbered 0 to 7) are indicated. In thisexample, there are regular LTE denials such that processes 0 and 4 areperiodically (every second time) denied.

A periodic LTE-denial of period 9 ms impacts same HARQ process only onceevery eight LTE-denials.

Periodic denial without taking into account the HARQ behavior may havehighly negative effects even with a low amount of denial: it may lead toa weaker link (best case) or HARQ failure (worst case). A weaker linkmay lead to eNodeB link adaptation, reduced resource allocation whileHARQ failure may lead either to data loss (RLC in unacknowledged mode)or to a RLC re-transmission with corresponding delay.

It is desirable to avoid applying LTE-denial periods which have suchnegative impact on HARQ. However, LTE-denial requirements may come fromapplications/codecs on the connectivity (CWS) side and many codecs haveperiodic requirements. In the following, mechanisms for smart LTEdenial, enabling periodic LTE-denial to support application/codecrequirements while minimizing its impact on the HARQ processes, oravoiding periodic LTE-denial when applicable.

For example, following provisions can be taken in applying LTE-denial tominimize impact on HARQ

-   -   Bursty denial: when there is no stringent requirements from        applications/codecs for periodic medium access (e.g. in case of        HTTP traffic carried over WLAN), the denied subframes are        grouped together (in bursts of time-contiguous sub frames) to        minimize the number of successive denials of a given HARQ        process (i.e. of denials of TTIs allocated to the same HARQ        process). For example, infrequent bursts with duration lower        than 8 ms impact each HARQ process at most once. Therefore, it        is likely to be completely mitigated by the HARQ.    -   Smart denial: when bursty denial cannot be applied, a denial        pattern is generated which minimizes the impact over HARQ while        ensuring periodicity requirements. This pattern is designed to        maximize time spacing between successive denials (cancellation)        of sub-frames carrying a given HARQ process:        -   This approach is optimal with respect to LTE link robustness            preservation (HARQ process protection)        -   Requirements on periodicity are fulfilled in average (the            LTE-denial is performed with the required period in average            over the full LTE-denial pattern). The pattern includes            varying the period between two LTE denials.        -   Avoid underflow/overflow for codec with periodic behavior

The general pattern generation algorithm for smart LTE denial may forexample be as follows:

Requirements:

-   -   P: period requirement (in ms)    -   N: duration requirement (in ms)    -   W: HARQ window length (8 ms for UL)

Algorithm:

-   -   Find P1<=P such that        -   [(MOD(P1,W)>=N) OR (MOD(P1,W)>=W−N)]            -   AND        -   (MOD(P1,W)+N) is even    -   If (P1=P)

apply P continuously

-   -   else    -   apply K1 times P1 with K1=W-abs(P−P1)    -   apply K2 times P1+W with K2=P−P1

A simple implementation example of this algorithm is described herebelow:

-   -   P1=P-abs(mod(P,W)−N)    -   P2=P1+W    -   K1=W−(P−P1)    -   K2=P−P1

An example is illustrated in FIG. 28. Along a second time line 2802, ULsub-frame denial and the allocation of the TTIs to HARQ processes areindicated, wherein the periods between the LTE denials has beendetermined according to the above algorithm. In this case, the LTEdenial pattern period P1 is applied K1 times and P2 is applied K2 times.As can be seen, it is avoided that TTIs allocated to the same HARQprocesses are periodically denied.

It should be noted that this pattern generation algorithm is applicableautonomously in the mobile terminal 105. It is also potentiallyapplicable for 3GPP-Release 11 IDC where the possibility to have LTE gapcreation decided at eNodeB level is under discussion. In this casedefinition of LTE denial patterns may be required and the ones describedabove may be optimal from a robustness point of view.

In the following, a mechanism for Smart VoLTE (Voice over LTE)-BT HFPcoexistence is described.

In this use case, the mobile terminal 105 is assumed to be connected toan earphone via BT and a voice call is received or placed over LTE(VoLTE). It is further assumed that the mobile terminal 105 acts as amaster BT device (in other words the BT entity in the mobile terminal105 is assumed to have the master role). If this is not the case, a BTRole Switch command may be issued.

Bluetooth communications are organized in piconets. with a single mastercontrolling the traffic allocation over 625 μs long time slots. This isillustrated in FIG. 29.

FIG. 29 shows a transmission diagram.

The transmission diagram shows transmissions (TX) and receptions (RX) bya master device, a first slave device (slave 1) and a second slavedevice (slave 2). The master has transmission opportunities on evenslots while the slaves can transmit in odd slots only (based onallocations from the master). The slaves listens on all potential mastertransmissions, every 1.25 ms, except if they are in a sleep mode (sniff,park, hold modes) where this constraints are relaxed.

For an earphone connection, the BT entities are typically paired and inlow power mode (e.g. one traffic exchange every 50 to 500 ms). When acall starts, the BT entities switch into HFP profile (Hands FreeProfile) with very frequent periodic eSCO (extended SynchronousConnection Oriented) or SCO (Synchronous Connection Oriented) traffics.This is illustrated in FIG. 30.

FIG. 30 shows transmission diagrams 3001, 3002.

The first transmission diagram 3001 illustrates eSCO communicationbetween a master (M) and a slave (S) and the second transmission diagram3002 illustrates SCO communication between the master and the slave.

Typically, as illustrated in FIG. 30, for HFP eSCO set-up has a eightslots period with two consecutive slots dedicated to master and slavetransmission followed by retransmission opportunities and SCO set-up hasa six slots period with two consecutive slots dedicated to master andslave transmission followed by four idle slots and there is noretransmission opportunity.

It should be noted that once BT devices are paired, a piconet is createdand hence BT system clock and slot counter are on. For example, the oddand even slots are then determined. So an attempt to synchronize theBluetooth system clock with respect to LTE system clock may not bepossible after piconet establishment, neither defining odd and evenslots. It should further be noted that the term TTI herein refers to theLTE TTI (1 ms) and Ts refers to the BT time slot duration (0.625 ms).

In the following, protection of BT eSCO is described. This is applicableto the case where a Bluetooth entity (e.g. realized by the secondtransceiver 1018) is using the HFP profile to carry voice from/to theheadset with eSCO traffic.

FIG. 31 shows a transmission diagram 3100.

A top time line 3101 represents VoLTE traffic in LTE-FDD UL over the air(1 ms grid). The HARQ process is synchronous with a 8 ms period and thevoice codec has a 20 ms period.

Sub frames with T and RTn labels correspond to the initial transmissionof a VoLTE sub-frame and to its n-th retransmission (in the sense ofHARQ retransmission). VoLTE original sub-frames are illustrated by afirst hatching 3103 and potential retransmission are illustrated by asecond hatching 3104.

A bottom time line 3102 shows the Bluetooth HFP traffic, seen from themaster point of view and based on eSCO packets. BT slots with secondhatching 3104 corresponds to potential BT retransmissions as per eSCOtraffic definition.

Due to both traffic characteristics (periods and duration), applying MACprotocol synchronization can allow efficient coexistence between VoLTEand BT HFP operations. Two different trade-offs are possible, a firstone where only the BT-HFP-eSCO initial reception is protected from LTEUL interference and a second one where both BT-HFP-eSCO initialreception and retransmitted slot reception are protected.

Reception of the original packet transmitted by the BT slave can beprotected from the LTE re-transmission under following conditions:

-   -   Protection from T        -   mod(D₀,5TTI)>=TTI−Ts OR mod(D₀,5TTI)<=5TTI−2 Ts    -   Protection from RT1        -   mod(D₀,5TTI)<=3TTI−2 Ts OR mod(D₀,5TTI)>=4TTI−Ts    -   Protection from RT2        -   mod(D₀,5TTI)<=TTI−2 Ts OR mod(D₀,5TTI)>=2TTI−Ts    -   Protection from RT3        -   mod(D₀,5TTI)<=4TTI−2 Ts OR mod(D₀,5TTI)>=5 TTI−Ts

Reception of the packet re-transmitted by the BT slave can be protectedfrom the LTE re-transmission under following conditions:

-   -   Protection from T        -   mod(D₀,5TTI)>=4TTI OR mod(D₀,5TTI)<=3TTI−Ts    -   Protection from RT1        -   mod(D₀,5TTI)<=TTI−Ts OR mod(D₀,5TTI)>=2TTI    -   Protection from RT2        -   mod(D₀,5TTI)<=4TTI−Ts OR mod(D₀,5TTI)>=0    -   Protection from RT3        -   mod(D₀,5TTI)<=2TTI−Ts OR mod(D₀,5TTI)>=3 TTI

As a first approach for VoLTE and BT eSCO coexistence, BT may beprotected from LTE TX, ReTx1, ReTx2, ReTX3 (i.e. protected of the firsttransmission and the first three retransmissions of a packet), withoutBT retry protection.

In this case, the BT initial packet exchange (1TX slot+1 RX slot) isprotected from the LTE UL transmissions as long as the LTE does notretransmit four times consecutively for the same HARQ process. BTretransmission if any may be jammed by LTE UL transmission. This may berealized by requiring the BT master initial packet transmission isdelayed vs LTE initial sub frame transmission by D₀ with 2TTI−Ts<=mod(D₀, 5TTI)<=3 TTI−2 Ts, e.g. 1375 μs<=mod(D₀,5 ms)<=1750 μs. Anexample is shown in FIG. 32.

FIG. 32 shows a transmission diagram 3200.

A top time line 3201 represents VoLTE traffic in LTE-FDD UL. Sub frameswith T and RTn labels correspond to the initial transmission of a VoLTEsub-frame and to its n-th retransmission (in the sense of HARQretransmission). VoLTE original sub-frames are illustrated by a firsthatching 3103 and potential retransmission are illustrated by a secondhatching 3104.

A bottom time line 3102 shows the Bluetooth HFP traffic, seen from themaster point of view and based on eSCO packets. BT slots with secondhatching 3104 corresponds to potential BT retransmissions as per eSCOtraffic definition.

As a second approach for VoLTE and BT eSCO coexistence, BT and BT repeat(i.e. BT packet retransmission) may be protected from LTE TX and ReTx1(i.e. from packet transmissions and the first packet retransmission). Inthis case, the BT initial packet exchange (1TX slot+1 RX slot) and itspotential first re-transmission is protected from the LTE ULtransmissions as long as the LTE system does not retransmit two timesconsecutively for the same HARQ process. If LTE system retransmits morethan two times some BT transmissions/retransmissions may be jammed. Thismay be realized by requiring that the BT master initial packettransmission is delayed vs. LTE initial sub frame transmission by D₁with D₁=TTI−Ts. For example, mod(D₁,5 ms)=375 us for eSCO and eSCOrepeat protection from LTE T and RT1. This transmission scenariocorresponds to the one shown in FIG. 31.

As a third approach for VoLTE and BT eSCO coexistence BT may beprotected from LTE TX, ReTx1. BT retry is not protected.

In this case, the BT initial packet exchange (1TX slot+1 RX slot) isprotected from the LTE UL transmissions as long as the LTE does notretransmit two times consecutively for the same HARQ process. If LTEretransmits more than two times some BT transmission/retransmission maybe jammed.

This may be realized by requiring that BT master initial packettransmission is delayed vs LTE initial sub frame transmission by D₀ withTTI−Ts<=mod(D₃,5 TTI)<=3 TTI−2 Ts. For example, 375 μs<=mod(D₃,5ms)<=1625 us for eSCO protection from LTE T, RT1. This transmissionscenario corresponds to the one shown in FIG. 31.

As a further approach BT SCO may be protected as follows. According toBluetooth the HFP profile may be used to carry voice from/to a headsetwith SCO traffic which occupies ⅓ of the communication medium time andhas no retransmission capability. An example is given in FIG. 33.

FIG. 33 shows a transmission diagram 3300.

A top time line 3301 represents VoLTE traffic in LTE-FDD UL. Sub frameswith T and RTn labels correspond to the initial transmission of a VoLTEsub-frame and to its n-th retransmission (in the sense of HARQretransmission). VoLTE original sub-frames are illustrated by a firsthatching 3103 and potential retransmission are illustrated by a secondhatching 3104.

A bottom time line 3102 shows the Bluetooth HFP traffic, seen from themaster point of view and based on SCO packets.

Two thirds of the BT packet exchange (1TX slot+1 RX slot) are protectedfrom the LTE UL transmissions. If some LTE retransmission occurs it islikely to jam some more BT slots. This can be realized by requiring thatBT delayed vs LTE active sub-frame start between TTI−Ts and TTI andTTI−Ts<=mod(D₂,6 Ts)<=TTI. For example, 375 μs<=mod(D₂, 3.75 ms)<=1 msfor minimum LTE VoLTE interference over SCO traffic. If D₂ is not withinthis range, then two thirds of the SCO packet may be jammed by the VoLTEsub-frame transmissions.

In summary, the delays or range of delays between VoLTE Tx and BT masterTx identified above (which may be considered as optimum) provide minimumcollision likelihood between VoLTE subframe transmissions and BT HFPpacket receptions. The delay requirements are derived corresponding toeSCO packets usage for BT HFP profile or SCO packets usage.

Usage of eSCO packet may be desirable as it coexists much better withthe VoLTE traffic pattern. If SCO is used one third of the BT packets islost due to collision with VoLTE UL sub frames, and it cannot be solvedvia LTE denial of this frames as it the effect on call quality would beworse (20 ms loss vs 5 ms loss).

Also among eSCO solutions, the third approach may be desirable because:

-   -   it is sufficient to completely protect BT initial receptions    -   its delay requirements are quite loose (2×BT Tslots); this can        be exploited in case of LTE handover during the call.

A possible concept may be as follows:

A) call set-up

-   -   1) BT Pairing which typically happens prior to VoLTE call        establishment is done without any specific coexistence        constraints.    -   2) When the LTE call is established, information of the        periodically allocated sub-frames (SPS based) is passed to the        BT added in NRT messaging. It may for example be available 5 to        10 ms after the SPS pattern is applied.    -   3) The BT master then interpret the SPS indication message        (period, duration, offset) and use the LTE frame sync RT signal        as a sync reference.    -   4) When establishing the eSCO/SCO traffic, the BT master        allocates the BT slots which fulfill the delay requirements with        respect to VoLTE transmissions (which is always possible as for        the third approach the delay is 2×Tslot).

B) LTE Handover

When LTE performs handover during the VoLTE call from a first cell to asecond cell, the LTE system clock in the first cell may differ in phasefrom the LTE system clock in the second cell (or second sector). SPSallocation may be different as well. As a consequence the delay betweenBT and VoLTE traffic patterns may not be fulfilled anymore:

-   1) Handover and new SPS allocation may then be provided to BT via    NRT messaging-   2) BT master may change BT slots allocation for the eSCO traffic in    order to fulfill again the delay requirement (always possible only    with the third approach described above).

It should be noted that due to the absence of a timestamp mechanism, itmay not be guaranteed yet that BT can derive directly the VoLTE subframepositions from the SPS indication in NRT messaging. If not, the BTentity may detect them via monitoring of the LTE UL gap envelop (RTinterface) using the SPS period information. As it may take severalVoLTE cycles to acquire VoLTE sync in this way, the BT may do a blindeSCO scheduling at start-up and reschedule it once the VoLTE subframeshave been identified.

This mechanism may be seen to be optimized for VoLTE with 20 ms period,however it may be used for any SPS based LTE traffic. Only the delayrequirements may be adapted.

In summary, for LTE-WLAN/BT coexistence in context of protocolmitigations, the following may be provided/performed:

-   -   Coexistence-friendly handover    -   SR postponing    -   Ignoring UL grant    -   LTE denial control (algorithm with monitoring of packet error        rate)    -   Minimizing the impact of LTE denial over LTE HARQ and hence on        the LTE link robustness (e.g. by a corresponding algorithm)    -   Minimizing the impact of BT HFP traffic over VoLTE traffic

According to one aspect of this disclosure, a radio communication deviceis provided as illustrated in FIG. 34.

FIG. 34 shows a radio communication device 3400.

The radio communication device 3400 includes a first transceiver 3401configured to transmit and receive signals in accordance with a CellularWide Area radio communication technology and a second transceiver 3405configured to transmit and receive signals in accordance with a ShortRange radio communication technology or a Metropolitan Area System radiocommunication technology. The radio communication device 3400 furtherincludes a first processor 3403 configured to control the firsttransceiver 3401 and a second processor 3404 configured to control thesecond transceiver 3402; wherein the first processor 3403 is configuredto control the first transceiver 3401 to transmit signals in accordancewith a predefined transmitting schedule, wherein the first processor3403 is further configured to control the first transceiver 3401 to omittransmitting signals within at least one of a time period and afrequency band provided for signal transmission of the first transceiver3401 in accordance with the predefined transmitting schedule.

It should be noted that although a connection of the first transceiver3401 and the second transceiver 3402 via the processors 3403, 3404 isillustrated, the first transceiver 3401 and the second transceiver 3402may also be directly connected.

The predefined transmitting schedule may include a transmitting andreceiving frame including at least one of time slots and frequency bandsfor transmitting and receiving signals by the first transceiver.

The first processor may be configured to control the first transceiverto omit transmitting signals within a subframe of the transmitting andreceiving frame provided for signal transmission of the firsttransceiver.

The first processor may be configured to select the at least one of atime period and a frequency band in which the transceiver is controlledto omit transmitting signals in accordance with an automatic repeatrequest mechanism provided in accordance with the Cellular Wide Arearadio communication technology.

For example, the automatic repeat request mechanism includes a hybridautomatic repeat request mechanism.

For example, the automatic repeat request mechanism includes a pluralityof transmission processes, each process being provided for transmissionof a portion of the data to be transmitted by the first transceiver.

The first processor may be configured to select the at least one of atime period and a frequency band in which the transceiver is controlledto omit transmitting signals in accordance with the characteristic ofthe selection of the processes wherein the at least one of the timeperiod and the frequency band overlap with different processes.

The automatic repeat request mechanism may include a plurality oftransmission processes, each process being provided for transmission ofa portion of the data to be transmitted by the first transceiver whereinthe processes are selected for the transmission of the data in aperiodic manner.

The first processor may be configured to select the at least one of atime period and a frequency band in which the transceiver is controlledto omit transmitting signals taking the periodicity of the processesinto account.

The first processor may be configured to select the at least one of atime period and a frequency band in which the transceiver is controlledto omit transmitting signals using the same process within a predefinednumbers of subsequent process cycles.

The first processor may be configured to select the at least one of atime period and a frequency band in which the transceiver is controlledto omit transmitting signals wherein each process is selected once foromitting transmission of signals before the same process is selected fora second time for omitting transmission of signals.

The first processor may be configured to select at least one of aplurality of consecutive time periods and a plurality of consecutivefrequency bands in which the transceiver is controlled to omittransmitting signals using the same process within a respective processcycle.

The first processor may be configured to select at least one of aplurality of consecutive time periods and a plurality of consecutivefrequency bands in which the transceiver is controlled to omittransmitting signals using the same process within a respective processcycle, wherein the sum of the plurality of consecutive time periods orthe sum of the plurality of consecutive frequency bands is smaller thanthe process cycle time or frequency provided for one complete processcycle.

The first processor may be configured to select at least one of aplurality of consecutive time periods and a plurality of consecutivefrequency bands in which the transceiver is controlled to omittransmitting signals using the same process within a respective processcycle, wherein over a plurality of process cycles an average period ofthe selected at least one of a plurality of consecutive time periods anda plurality of consecutive frequency bands substantially corresponds toa predefined period of the process cycle.

According to one aspect of this disclosure, the first processor isconfigured to select the at least one of a time period and a frequencyband in which the transceiver is controlled to omit transmitting signalsas a transmission denial pattern and to store the transmission denialpattern.

The radio communication device is for example configured as a radiocommunication terminal device.

The radio communication device may be configured to receive thetransmission denial pattern from a radio communication base stationdevice.

The first transceiver may be configured to transmit and receive signalsin accordance with a Third Generation Partnership Project radiocommunication technology.

The first transceiver may be configured to transmit and receive signalsin accordance with a 4G radio communication technology.

For example, the first transceiver is configured to transmit and receivesignals in accordance with a Long Term Evolution radio communicationtechnology.

According to one aspect of this disclosure, the second transceiver isconfigured to transmit and receive signals in accordance with a ShortRange radio communication technology selected from a group consistingof:

-   -   Bluetooth radio communication technology;    -   Ultra Wide Band radio communication technology;    -   Wireless Local Area Network radio communication technology;    -   Infrared Data Association radio communication technology;    -   Z-Wave radio communication technology;    -   ZigBee radio communication technology;    -   HIgh PErformance Radio LAN radio communication technology;    -   IEEE 802.11 radio communication technology; and    -   Digital Enhanced Cordless Telecommunications radio communication        technology.

According to one aspect of this disclosure, the second transceiver isconfigured to transmit and receive signals in accordance with aMetropolitan Area System radio communication technology selected from agroup consisting of:

-   -   Worldwide Interoperability for Microwave Access radio        communication technology;    -   WiPro radio communication technology;    -   High Performance Radio Metropolitan Area Network radio        communication technology; and    -   802.16m Advanced Air Interface radio communication technology.

According to one aspect of this disclosure, a method for operating aradio communication device as illustrated in FIG. 35 is provided.

FIG. 35 shows a flow diagram 3500.

In 3501 a first transceiver transmitts and receives signals inaccordance with a Cellular Wide Area radio communication technology.

In 3502, a second transceiver transmits and receives signals inaccordance with a Short Range radio communication technology or aMetropolitan Area System radio communication technology.

In 3503 a first processor controls the first transceiver, wherein firstprocessor controls the first transceiver to transmit signals inaccordance with a predefined transmitting schedule, wherein the firstprocessor further controls the first transceiver to omit transmittingsignals within at least one of a time period and a frequency bandprovided for signal transmission of the first transceiver in accordancewith the predefined transmitting schedule.

In 3504 a second processor controls the second transceiver.

The predefined transmitting schedule may include a transmitting andreceiving frame including at least one of time slots and frequency bandsfor transmitting and receiving signals by the first transceiver.

The first processor may control the first transceiver to omittransmitting signals within a subframe of the transmitting and receivingframe provided for signal transmission of the first transceiver.

The first processor may select the at least one of a time period and afrequency band in which the transceiver is controlled to omittransmitting signals in accordance with an automatic repeat requestmechanism provided in accordance with the Cellular Wide Area radiocommunication technology.

For example, the automatic repeat request mechanism includes a hybridautomatic repeat request mechanism.

For example, the automatic repeat request mechanism includes a pluralityof transmission processes, each process being provided for transmissionof a portion of the data to be transmitted by the first transceiver.

According to one aspect of this disclosure, the first processor selectsthe at least one of a time period and a frequency band in which thetransceiver is controlled to omit transmitting signals in accordancewith the characteristic of the selection of the processes wherein the atleast one of the time period and the frequency band overlap withdifferent processes.

The automatic repeat request mechanism may include a plurality oftransmission processes, each process being provided for transmission ofa portion of the data to be transmitted by the first transceiver whereinthe processes are selected for the transmission of the data in aperiodic manner.

For example, the first processor selects the at least one of a timeperiod and a frequency band in which the transceiver is controlled toomit transmitting signals taking the periodicity of the processes intoaccount.

The first processor may select the at least one of a time period and afrequency band in which the transceiver is controlled to omittransmitting signals using the same process within a predefined numbersof subsequent process cycles.

The first processor may select the at least one of a time period and afrequency band in which the transceiver is controlled to omittransmitting signals wherein each process is selected once for omittingtransmission of signals before the same process is selected for a secondtime for omitting transmission of signals.

The first processor may select at least one of a plurality ofconsecutive time periods and a plurality of consecutive frequency bandsin which the transceiver is controlled to omit transmitting signalsusing the same process within a respective process cycle.

The first processor may be configured to select at least one of aplurality of consecutive time periods and a plurality of consecutivefrequency bands in which the transceiver is controlled to omittransmitting signals using the same process within a respective processcycle, wherein the sum of the plurality of consecutive time periods orthe sum of the plurality of consecutive frequency bands is smaller thanthe process cycle time or frequency provided for one complete processcycle.

The first processor may select at least one of a plurality ofconsecutive time periods and a plurality of consecutive frequency bandsin which the transceiver is controlled to omit transmitting signalsusing the same process within a respective process cycle, wherein over aplurality of process cycles an average period of the selected at leastone of a plurality of consecutive time periods and a plurality ofconsecutive frequency bands substantially corresponds to a predefinedperiod of the process cycle.

The first processor may select the at least one of a time period and afrequency band in which the transceiver is controlled to omittransmitting signals as a transmission denial pattern and stores thetransmission denial pattern.

The method may further include receiving the transmission denial patternfrom a radio communication base station device.

According to one aspect of this disclosure, the first transceivertransmits and receives signals in accordance with a Third GenerationPartnership Project radio communication technology.

Accordingt to one aspect of this disclosure, the first transceivertransmits and receives signals in accordance with a 4G radiocommunication technology.

For example, the first transceiver transmits and receives signals inaccordance with a Long Term Evolution radio communication technology;

The second transceiver may transmit and receive signals in accordancewith a Short Range radio communication technology selected from a groupconsisting of:

-   -   Bluetooth radio communication technology;    -   Ultra Wide Band radio communication technology;    -   Wireless Local Area Network radio communication technology;    -   Infrared Data Association radio communication technology;    -   Z-Wave radio communication technology;    -   ZigBee radio communication technology;    -   HIgh PErformance Radio LAN radio communication technology;    -   IEEE 802.11 radio communication technology; and    -   Digital Enhanced Cordless Telecommunications radio communication        technology.

The second transceiver may also transmit and receive signals inaccordance with a Metropolitan Area System radio communicationtechnology selected from a group consisting of:

-   -   Worldwide Interoperability for Microwave Access radio        communication technology;    -   WiPro radio communication technology;    -   High Performance Radio Metropolitan Area Network radio        communication technology; and    -   802.16m Advanced Air Interface radio communication technology.

In the radio communication device 3400, the first transceiver forexample corresponds to the LTE subsystem 2101, the second transceivercorresponds to the WLAN/Bluetooth communication circuit 2102. The firstprocessor and the second processor may correspond to correspondingcontrollers of these communication modules. For example, the firstprocessor may correspond to the communication circuit 2104. The firstprocessor may for example correspond (or include) the the RT arbitrationentity 2111. Alternatively, any of the corresponding tasks may becarried out by the application processor 2105.

Further examples for LTE/BT/WLAN coexistence are given in the following.

The NRT arbiter 2108 uses a mixture of application requirements (fromconnectivity and LTE apps) and context information from both cores, i.e.both LTE and Bluetooth or WLAN (e.g. band, bandwidth, EARFCN) toarbitrate and indicate static information such as selected frequencybands or selected power levels to LTE and connectivity (i.e. Bluetoothor WLAN). It may also provide indications to the RT arbiter located inLTE subsystem.

For example, the NRT arbiter 2108 does not arbitrate between WLAN and BT(arbitration between these is for example done in the connectivitychip).

When the LTE subsystem camps on a new cell, the LTE SW indicates the newLTE Information to the NRT 2108 arbiter and this information is storedto be reused in NRT algorithms e.g. according to 2407, 2408, 2410.

The NRT arbiter may then run an NRT algorithm protecting BT fromLTE-FDD.

This algorithm is run in the NRT arbitration unit 2108. It is split intwo subroutines:

Subroutine 1 is activated each time the LTE subsystem 2101 camps on anew cell while BT is active (BT state is for example indicatedseparately via the NRT coexistence interface). It determines thefrequency range where BT can co-run safely with LTE in worst casecondition. Subroutine 1 is illustrated in FIG. 36.

FIG. 36 shows a message flow diagram 3600.

The message flow takes place between an NRT arbiter 3601 correspondingto the NRT arbiter 2108 and a BT communication circuit 3602corresponding to the WLAN/BT communication circuit 2102.

In 3603, the NRT arbiter 3601 loads parameters from a non-volatilememory. These may include the parameters Lant (antenna isolation)between LTE Tx and WLAN/BT Rx, P_LTE_max (maximum power of LTE), Nminrequired minimum number of BT channels to apply AFH, BT_max_PSD (indBm/Mhz) (maximum BT power spectral density), BT_MAX_BLKR (BT maximumtolerable blocker interference), BT_MAX_LIN (BT maximum tolerable InBand noise interference), L_OOB( ) (contains LTE transmitter Out Of Bandspectrum (relative to In Band power)) and ISM RX filter shape parameters(e.g. Band7Filter(, 1) (or RxFilter(,1)).

In 3604, the NRT arbiter 3601 calculates BT_SAFE_RX_FREQ_MIN andBT_SAFE_RX_FREQ_MAX

based on

-   -   LTE band    -   BT max tolerable blocker interference    -   BT max tolerable In Band noise interference    -   LTE freq    -   ISM RX filter shape    -   LTE Tx OOB noise    -   Antenna isolation    -   BT_SAFE_RX_FREQ_MIN, BT_SAFE_RX_FREQ_MAX give the ISM frequency        range (1 Mhz accuracy) fulfilling co-running targets (de-sense,        throughput loss) in worst case (LTE max power, max bandwidth, BT        RX @sensitivity level). These are for example static such that        they can be pre-calculated and stored in a look-up table.

In 3605, the NRT arbiter 3601 communicates BT_SAFE_RX_FREQ_MIN andBT_SAFE_RX_FREQ_MAX to the BT communication circuit 3602.

In 3606, the BT communication circuit 3602 stores BT_SAFE_RX_FREQ_MINand BT_SAFE_RX_FREQ_MAX and confirms reception of these parameters in3607. Subroutine 2 is illustrated in FIG. 37.

FIG. 37 shows a message flow diagram 3700.

The message flow takes place between an NRT arbiter 3701 correspondingto the NRT arbiter 2108 and a BT communication circuit 3702corresponding to the WLAN/BT communication circuit 2102.

Subroutine 2 is activated each time the BT communication circuit 3702modifies its AFH map in 3703.

This modification is for example done autonomously on BT side either fortraffic purpose or for coexistence purpose.

In 3704, the BT communication circuit 3702 then stores the minimum BTfrequency and the maximum BT frequency according to the changed AFH map.

In 3705, the BT core (i.e. the BT communication circuit 3702) assesseswhether its full AFH map is contained in the safe frequency range andindicates the result to NRT arbiter 3701 (in this example by means of asingle bit indication) in 3706. When receiving the information the NRTarbiter 3701 enables/disables the real time interface (or a subset ofthe real interface where differentiation between BT and WLAN ispossible) in 3707 and sends a confirmation to the BT communicationcircuit 3702 in 3708.

In case of no way to differentiate between WiFi and BT, if theparameters BT_RX_KILL and WIFI_RX_KILL (see FIG. 39) are both disabledthen the real time interface is disabled. Otherwise the real timeinterface is enabled.

Further, the NRT arbiter may run an NRT algorithm protecting WLAN fromLTE-FDD.

This algorithm is run in the NRT arbitration unit 2108. It is split intwo subroutines:

Subroutine 1 is activated each time the LTE subsystem 2101 camps on anew cell while WLAN is active (WLAN state is for example indicatedseparately via the NRT coexistence interface). It determines thefrequency range where WLAN can co-run safely with LTE. Subroutine 1 isillustrated in FIG. 38.

FIG. 38 shows a message flow diagram 3800.

The message flow takes place between an NRT arbiter 3801 correspondingto the NRT arbiter 2108 and a WLAN communication circuit 3802corresponding to the WLAN/BT communication circuit 2102.

In 3803, the NRT arbiter 3801 loads parameters from a non-volatilememory. These may include the parameters Lant (antenna isolation)between LTE Tx and WLAN/BT Rx, P_LTE_max (maximum power of LTE),WLAN_max_PSD (maximum WLAN power spectral density), WLAN_MAX_BLKR (WLANmaximum tolerable blocker interference), WLAN_MAX_LIN (WLAN maximumtolerable In Band noise interference), L_OOB( ) (contains LTEtransmitter Out Of Band spectrum (relative to In Band power)) and ISM RXfilter shape parameters (e.g. Band7Filter(,BW) (or RxFilter (,BW)).Band7Filter(, BW) is the ISM RX filter shape integrated over LTE cellBW. 5 Band7Filter tables are stored in NVM corresponding to BW=1, 5, 10,15, 20 Mhz).

In 3804, the NRT arbiter 3801 calculates WLAN_SAFE_RX_FREQ_MIN andWLAN_SAFE_RX_FREQ_MAX

based on

-   -   LTE band    -   WLAN max tolerable blocker interference    -   WLAN max tolerable In Band noise interference    -   LTE freq    -   ISM RX filter shape    -   LTE Tx OOB noise    -   Antenna isolation    -   WLAN_SAFE_RX_FREQ_MIN, WLAN_SAFE_RX_FREQ_MAX give the ISM        frequency range (1 Mhz accuracy) fulfilling co-running targets        (de-sense, throughput loss) in worst case (LTE max power, max        bandwidth, WLAN RX @sensitivity level). These are for example        static such that they can be pre-calculated and stored in a        look-up table.

In 3805, the NRT arbiter 3801 communicates WLAN_SAFE_RX_FREQ_MIN andWLAN_SAFE_RX_FREQ_MAX to the WLAN communication circuit 3802.

In 3806, the WLAN communication circuit 3802 storesWLAN_SAFE_RX_FREQ_MIN and WLAN_SAFE_RX_FREQ_MAX and confirms receptionof these parameters in 3807. Subroutine 2 is illustrated in FIG. 39.

FIG. 39 shows a message flow diagram 3900.

The message flow takes place between an NRT arbiter 3901 correspondingto the NRT arbiter 2108 and a WLAN communication circuit 3902corresponding to the WLAN/BT communication circuit 2102.

Subroutine 2 is activated each time the WLAN communication circuit 3902modifies its list of active WLAN channels in 3903.

This modification is for example done autonomously on WLAN side eitherfor traffic purpose or for coexistence purpose.

In 3904, the WLAN communication circuit 3902 then stores the minimumWLAN frequency and the maximum WLAN frequency according to the changedlist of active WLAN channels.

In 3905, the WLAN core (i.e. the WLAN communication circuit 3902)assesses whether its WLAN channels are in the safe frequency range andindicates the result to NRT arbiter 3901 (in this example by means of asingle bit indication) in 3906. When receiving the information the NRTarbiter 3901 enables/disables the real time interface (or a subset ofthe real interface where differentiation between BT and WLAN ispossible) in 3907 and sends a confirmation to the WLAN communicationcircuit 3902 in 3908. In case of no way to differentiate between WiFiand BT, if the parameters BT_RX_KILL (see FIG. 39) and WIFI_RX_KILL areboth disabled then the real time interface is disabled. Otherwise thereal time interface is enabled.

In the following, further examples for the non real time applicationinterface, the non real time coexistence interface and parameters storedin non-volatile memory are given.

The NRT Application Interface transfers messages carrying applicationinformation about connectivity and LTE applications. The “I/O” field hasthe following meaning for parameters: “I” means from AP to NRTA, “O”means from NRTA to AP.

TABLE 11 Non Real Time applications coexistence interface Info ParameterBits I/O Description PERIOD 16 I/O Required application service periodms. Overrides any previous use. DURATION 6 I/O Required applicationservice duration ms. Overrides any previous use.

The NRT coexistence interface transfers messages carrying CWSinformation. The “I/O” field has the following meaning for parameters:“I” means from CWS to NRTA, “O” means from NRTA to CWS.

TABLE 12 Non Real Time coexistence interface Info Parameter bits I/ODescription WLAN_ACTIVE 1 I NRT controller is enabled by this indication-> Replace IS_COEX previously in NRT Apps I/F WLAN_SAFE_RX 1 IIndication that WLAN operation stays withing the safe freq range (usedto disable the RT I/F or the WLAN portion of it) WLAN_BANDWIDTH 2 I WLANBandwidth 0 = 20 MHz, 1 = 40 MHz, 2 = 80 MHz, 3 = Invalid BT_ACTIVE 1 INRT controller is enabled by this indication -> Replace IS_COEXpreviously in NRT Apps I/F BT_SAFE_RX 1 I Indication that BT operationstays withing the safe freq range (used to disable the RT I/F or the BTportion of it) LTE_ACTIVE 1 O Used by CWS -> indication to CWS that LTEcorrunning constraints are released WLAN_LTE_EN 1 O Transmission of WLANpackets shorter than 2 LTE OFDM symbols For future use: LTE-TDD onlyLTE_SPS_PATTERN 24 O SPS Periodicity (ms): 11 bits SPS event duration(ms): 9 bits SPS initial offset (sub-frame offset in first LTE framewhere SPS is applied): 4 bits TBC: Indicate periodic LTE activity to theconnectivity chip. This one can then exploit this for its ownscheduling. LTE_BITMAP 10 × 2 O 0 = Special subframe 1 = RX LTE subframe2 = TX LTE subframe For future use: Indicate LTE-TDD frame structure tothe connectivity cores. WLAN_SAFE_RX_FREQ_MIN 12 O Lower limit of freqrange where WLAN can receive during LTE Tx (worst case, static approach)In Mhz WLAN_SAFE_RX_FREQ_MAX 12 O Upper limit of freq range where WLANcan receive during LTE Tx (worst case, static approach) In MhzBT_SAFE_RX_FREQ_MIN 12 O Lower limit of freq range where BT can receiveduring LTE Tx (worst case, static approach) In Mhz BT_SAFE_RX_FREQ_MAX12 O Upper limit of freq range where BT can receive during LTE Tx (worstcase, static approach) In Mhz WLAN_TX_POWER 4 I/O WLAN Tx power (appliedor to be applied) For future use (LTE-TDD). To be used by NRT controllerto evaluate WLAN interference over LTE (usefull in tethering case whereWLAN Tx power can be reduced).

The following table lists examples for parameters stored in non-volatilememory used.

TABLE 13 NVM Parameters NVM Parameter NRT_capability BT_Max_PSDBT_channel_freq Nmin P_LTE_max L_OOB Band7Filter Lant

While the invention has been particularly shown and described withreference to specific aspects, it should be understood by those skilledin the art that various changes in form and detail may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims. The scope of the invention is thus indicated bythe appended claims and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to beembraced.

What is claimed is:
 1. An apparatus for reducing interference, theapparatus comprising: a first transceiver configured to transmit andreceive cellular wide area radio signals; a second transceiverconfigured to transmit and receive short range radio signals; and atleast one processor when executing a stored program code configured tocontrol the first transceiver to restrict transmit of cellular wide arearadio signals within portions of time for cellular wide area radiosignal transmission based on a hybrid automatic repeat request processof the cellular wide area radio transmission.
 2. The apparatus of claim1, wherein the at least one processor is further configured to controlthe second transceiver to receive the short range radio signals thatinterfere with the cellular wide area radio signals.
 3. The apparatus ofclaim 1, wherein the at least one processor is configured to control thefirst transceiver to restrict transmit of cellular wide area radiosignals within a subframe of a frame provided for cellular wide arearadio signal transmission.
 4. The apparatus of claim 1, wherein thehybrid automatic repeat request process comprises a plurality oftransmission processes, each process being provided for transmission ofa portion of data by the first transceiver.
 5. The apparatus of claim 4,wherein the at least one processor is further configured to control thefirst transceiver to restrict transmitting cellular wide area radiosignals in accordance with a characteristic of a selection of thetransmission processes; and wherein the portion of times that overlapwith different transmission processes.
 6. The apparatus of claim 4,wherein the at least one processor is further configured to control thefirst transceiver to restrict transmitting cellular wide area radiosignals based on periodicity of the transmission processes.
 7. Theapparatus of claim 1, wherein the at least one processor is configuredto control the first transceiver to restrict transmit of cellular widearea radio signals in accordance with a predetermined transmissionpattern and to store the predetermined transmission pattern.
 8. Theapparatus of claim 1, wherein the apparatus is a User Equipment.
 9. Theapparatus of claim 1, wherein the first transceiver is configured totransmit and receive Third Generation Partnership Project radio signals.10. The apparatus of claim 1, wherein the first transceiver isconfigured to transmit and receive 4G radio signals.
 11. The apparatusof claim 1, wherein the first transceiver is configured to transmit andreceive Long Term Evolution radio signals.
 12. The apparatus of claim 1,wherein the second transceiver is configured to transmit and receiveshort range radio signals selected from a group consisting of: Bluetoothradio signals; and Wireless Local Area Network radio signals.
 13. Theapparatus of claim 1, wherein the at least one processor comprises afirst processor configured to control the first transceiver and a secondprocessor configured to control the second transceiver.
 14. A mobileradio device for reducing interference of a radio circuit, the mobileradio device comprising: a first transceiver configured to transmit andreceive cellular wide area radio signals; a second transceiverconfigured to transmit and receive short range radio signals; at leastone processor when executing a stored program code configured to controlthe first transceiver to transmit signals based on a predefinedtransmitting schedule and restrict transmitting signals within a timeperiod for cellular wide area radio signal transmission based on thepredefined transmitting schedule, wherein the predefined transmittingschedule comprises a transmitting and receiving frame including timeslots for transmitting and receiving cellular wide area radio signals;and select the time period in which the first transceiver restrictstransmitting signals based on a hybrid automatic repeat request processof the cellular wide area radio signal transmission; and control thefirst transceiver to restrict transmitting signals during the timeperiod.
 15. The mobile radio device of claim 14, wherein the time periodcomprises a subframe of the transmitting and receiving frame.
 16. Themobile radio device of claim 14, wherein the hybrid automatic repeatrequest process comprises a plurality of transmission processes, eachtransmission process being provided for transmission of a portion ofdata to be transmitted by the first transceiver.
 17. The mobile radiodevice of claim 16, wherein the at least one processor is configured tocontrol the first transceiver to restrict transmitting cellular widearea radio signals in accordance with a characteristic of a selection ofthe transmission processes; and wherein the time period overlap withdifferent transmission processes.
 18. The mobile radio device of claim14, wherein the at least one processor is further configured to controlthe first transceiver to restrict transmitting cellular wide area radiosignals based on periodicity of the transmission processes.
 19. Themobile radio device of claim 14, wherein the at least one processor isfurther configured to control the first transceiver to restricttransmitting signals in accordance with a predetermined transmissionpattern and to store the predetermined transmission pattern.
 20. Themobile radio device of claim 14, wherein the mobile radio device is aUser Equipment.
 21. The mobile radio device of claim 14, wherein thefirst transceiver is configured to transmit and receive Third GenerationPartnership Project radio signals.
 22. The mobile radio device of claim14, wherein the first transceiver is configured to transmit and receive4G radio signals.
 23. The mobile radio device of claim 14, wherein thefirst transceiver is configured to transmit and receive Long TermEvolution radio signals.
 24. The mobile radio device of claim 14,wherein the second transceiver is configured to transmit and receiveshort range radio signals selected from a group consisting of: Bluetoothradio signals; and Wireless Local Area Network signals.
 25. Acommunication terminal, comprising: a first transceiver configured totransmit and receive cellular wide area radio signals, the firsttransceiver comprising one or more first frontend components and one ormore first antennas; a second transceiver configured to transmit andreceive short range radio signals, the second transceiver comprising oneor more second frontend components and one or more second antennas; atleast one memory; and at least one processor when executing a storedprogram code configured to control the first transceiver to restricttransmission of cellular wide area radio signals within portions of timefor cellular wide area radio signal transmission based on a hybridautomatic repeat request process of the cellular wide area radiotransmission.
 26. A non-transient computer readable medium having storedprogram code thereon which, when executed, implements an operation of anapparatus for reducing interference, comprising: transmitting andreceiving cellular wide area radio signals on a first transceiver;transmitting and receiving short range radio signals on a secondtransceiver; controlling the first transceiver and the secondtransceiver using at least one processor; and wherein the at least oneprocessor controls the first transceiver to restrict transmittingcellular wide area radio signals within portions of time for cellularwide area radio signal transmission of the first transceiver based on ahybrid automatic repeat request process provided in the cellular widearea radio communication technology.